diff --git a/bleeding.js b/bleeding.js
index 359a94f..f7e4e55 100644
--- a/bleeding.js
+++ b/bleeding.js
@@ -10,7 +10,10 @@ import styles from './styles'
 import { saveBleeding } from './db'
 import { formatDateForViewHeader } from './format'
 import { bleeding as labels } from './labels'
-import getCycleDay from './get-cycle-day'
+import cycleDayModule from './get-cycle-day-number'
+import { getCycleDaysSortedByDateView } from './db'
+
+const getCycleDay = cycleDayModule(getCycleDaysSortedByDateView())
 
 export default class Bleeding extends Component {
   constructor(props) {
@@ -40,7 +43,7 @@ export default class Bleeding extends Component {
     return (
       <View style={styles.container}>
         <Text style={styles.welcome}>{formatDateForViewHeader(day.date)}</Text>
-        <Text>Cycle day {getCycleDay()}</Text>
+        <Text>Cycle day {getCycleDay(day.date)}</Text>
         <Text>Bleeding</Text>
         <RadioForm
           radio_props={bleedingRadioProps}
diff --git a/day-view.js b/day-view.js
index 5f3e307..799d815 100644
--- a/day-view.js
+++ b/day-view.js
@@ -7,7 +7,10 @@ import {
 import styles from './styles'
 import { formatDateForViewHeader } from './format'
 import { bleeding as labels} from './labels'
-import getCycleDay from './get-cycle-day'
+import cycleDayModule from './get-cycle-day-number'
+import { getCycleDaysSortedByDateView } from './db'
+
+const getCycleDay = cycleDayModule(getCycleDaysSortedByDateView())
 
 export default class DayView extends Component {
   constructor(props) {
@@ -31,7 +34,7 @@ export default class DayView extends Component {
     return (
       <View style={styles.container}>
         <Text style={styles.welcome}>{formatDateForViewHeader(day.date)}</Text>
-        <Text>Cycle day {getCycleDay()}</Text>
+        <Text>Cycle day {getCycleDay(day.date)}</Text>
         <Text style={styles.welcome}>{bleedingLabel}</Text>
         <Button
           onPress={() => navigate('bleeding', { cycleDay: day })}
diff --git a/db.js b/db.js
index dd2648e..3ce8f12 100644
--- a/db.js
+++ b/db.js
@@ -1,8 +1,4 @@
-import realm from 'realm'
-
-let db
-let cycleDaysSortedbyTempValueView = []
-let bleedingDaysSortedByDate = []
+import Realm from 'realm'
 
 const TemperatureSchema = {
   name: 'Temperature',
@@ -36,21 +32,18 @@ const CycleDaySchema = {
   }
 }
 
-async function openDatabase() {
-  db = await realm.open({
-    schema: [
-      CycleDaySchema,
-      TemperatureSchema,
-      BleedingSchema
-    ],
-    // we only want this in dev mode
-    deleteRealmIfMigrationNeeded: true
-  })
-  // just for testing purposes, the highest temperature will be topmost
-  // because I was too layz to make a scroll view
-  cycleDaysSortedbyTempValueView = db.objects('CycleDay').filtered('temperature != null').sorted('temperature.value', true)
-  bleedingDaysSortedByDate = db.objects('CycleDay').filtered('bleeding != null').sorted('date', true)
-}
+const db = new Realm({
+  schema: [
+    CycleDaySchema,
+    TemperatureSchema,
+    BleedingSchema
+  ],
+  // we only want this in dev mode
+  deleteRealmIfMigrationNeeded: true
+})
+
+const cycleDaysSortedbyTempValueView = db.objects('CycleDay').filtered('temperature != null').sorted('temperature.value', true)
+const bleedingDaysSortedByDate = db.objects('CycleDay').filtered('bleeding != null').sorted('date', true)
 
 function saveTemperature(date, temperature) {
   db.write(() => {
@@ -62,6 +55,8 @@ function saveTemperature(date, temperature) {
   })
 }
 
+const getCycleDaysSortedByDateView = () => db.objects('CycleDay').sorted('date', true)
+
 function saveBleeding(cycleDay, bleeding) {
   db.write(() => {
     cycleDay.bleeding = bleeding
@@ -80,11 +75,18 @@ function getOrCreateCycleDay(localDate) {
   return result
 }
 
+function deleteAll() {
+  db.write(() => {
+    db.deleteAll()
+  })
+}
+
 export {
   cycleDaysSortedbyTempValueView,
-  openDatabase,
   saveTemperature,
   saveBleeding,
   getOrCreateCycleDay,
-  bleedingDaysSortedByDate
+  bleedingDaysSortedByDate,
+  getCycleDaysSortedByDateView,
+  deleteAll
 }
\ No newline at end of file
diff --git a/get-cycle-day-number.js b/get-cycle-day-number.js
index d7890ca..1c6d74f 100644
--- a/get-cycle-day-number.js
+++ b/get-cycle-day-number.js
@@ -1,54 +1,43 @@
-import moment from 'moment'
+import * as joda from 'js-joda'
 
-export default function config(opts) {
+const LocalDate = joda.LocalDate
+
+export default function config(bleedingDaysSortedByDateView, opts) {
   opts = opts || {
     // at the very minimum, a cycle can be a bleeding day
     // followed by a non-bleeding day, thus a length of 2
-    minCycleLengthInDays: 2
+    maxBreakInBleeding: 1
   }
 
-  return function getCycleDayNumber(unsorted, targetDate) {
+  return function getCycleDayNumber(targetDateString) {
     // sort the cycle days in descending order so we travel into
     // the past as we iterate over the array
     // also, to retrieve the number, we only need the cycle days before the target day
-    // TODO we can probably rely on the db to do the sorting for us
-    targetDate = moment(targetDate)
-    const sorted = unsorted
+    const targetDate = LocalDate.parse(targetDateString)
+    const withWrappedDates = bleedingDaysSortedByDateView
+      .filter(day => !day.bleeding.exclude)
       .map(day => {
-        day.date = moment(day.date)
+        day.wrappedDate = LocalDate.parse(day.date)
         return day
       })
-      .sort((a, b) => b.date.isAfter(a.date))
-    const firstDayBeforeTargetDayIndex = sorted.findIndex(day => day.date.isBefore(targetDate))
-    const cycleDays = sorted.slice(firstDayBeforeTargetDayIndex)
+    // TODO write test for what if there is no first day before?? aka no firstbleedingdaybeforeindex
+    const firstBleedingDayBeforeTargetDayIndex = withWrappedDates.findIndex(day => day.wrappedDate.isBefore(targetDate))
+    const cycleDays = withWrappedDates.slice(firstBleedingDayBeforeTargetDayIndex)
 
     const lastPeriodStart = cycleDays.find((day, i) => {
-      if (
-        isBleedingDay(day) &&
-        thereIsNoPreviousBleedingDayWithinTheThreshold(day, cycleDays.slice(i + 1), opts.minCycleLengthInDays)) {
-        return true
-      }
+      return thereIsNoPreviousBleedingDayWithinTheThreshold(day, cycleDays.slice(i + 1), opts.maxBreakInBleeding)
     })
 
     if (!lastPeriodStart) return null
 
-    // by default, moment.diff rounds down, so we get the decimal number
-    // and round it ourselves
-    const diffInDays = Math.round(targetDate.diff(lastPeriodStart.date, 'days', true))
+    const diffInDays = lastPeriodStart.wrappedDate.until(targetDate, joda.ChronoUnit.DAYS)
 
     // cycle starts at day 1
     return diffInDays + 1
   }
 }
 
-function thereIsNoPreviousBleedingDayWithinTheThreshold(bleedingDay, earlierCycleDays, threshold) {
-  // the bleeding day itself is included in the threshold, thus we subtract 1
-  const minCycleThresholdDate = moment(bleedingDay.date).subtract(threshold - 1, 'days')
-  return !earlierCycleDays.some(day => {
-    return day.date.isSameOrAfter(minCycleThresholdDate, 'day') && isBleedingDay(day)
-  })
-}
-
-function isBleedingDay(day) {
-  return day.bleeding && day.bleeding.value && !day.bleeding.exclude
+function thereIsNoPreviousBleedingDayWithinTheThreshold(bleedingDay, earlierCycleDays, allowedBleedingBreak) {
+  const periodThreshold = bleedingDay.wrappedDate.minusDays(allowedBleedingBreak + 1)
+  return !earlierCycleDays.some(({ wrappedDate }) => wrappedDate.equals(periodThreshold) || wrappedDate.isAfter(periodThreshold))
 }
\ No newline at end of file
diff --git a/get-cycle-day.js b/get-cycle-day.js
deleted file mode 100644
index 4930e24..0000000
--- a/get-cycle-day.js
+++ /dev/null
@@ -1 +0,0 @@
-export default () => 6
\ No newline at end of file
diff --git a/home.js b/home.js
index 3552246..101a7ea 100644
--- a/home.js
+++ b/home.js
@@ -5,18 +5,30 @@ import {
   Text
 } from 'react-native'
 import styles from './styles'
-import getCycleDay from './get-cycle-day'
+import cycleDayModule from './get-cycle-day-number'
+import { getCycleDaysSortedByDateView, deleteAll } from './db'
+import { LocalDate } from 'js-joda'
+
+const cycleDaysSortedByDateView = getCycleDaysSortedByDateView()
+const getCycleDayNumber = cycleDayModule(cycleDaysSortedByDateView)
+const now = new Date()
+const cycleDayNumber = getCycleDayNumber(LocalDate.of(now.getFullYear(), now.getMonth() + 1, now.getDate()))
+const welcomeTextWithCycleDay = `Welcome! Today is day ${cycleDayNumber} of your current cycle`
+const welcomeText = `Welcome! We don't have enough information to know what your current cycle day is`
 
 export default class Home extends Component {
   constructor(props) {
     super(props)
+    this.state = {
+      welcomeText: cycleDayNumber ? welcomeTextWithCycleDay : welcomeText
+    }
   }
 
   render() {
     const navigate = this.props.navigation.navigate
     return (
       <View style={styles.container}>
-        <Text style={styles.welcome}>Welcome! Today is day {getCycleDay()} of your current cycle</Text>
+        <Text style={styles.welcome}>{this.state.welcomeText}</Text>
         <Button
           onPress={() => navigate('temperatureList')}
           title="Edit symptoms for today">
@@ -25,7 +37,11 @@ export default class Home extends Component {
           onPress={() => navigate('calendar')}
           title="Go to calendar">
         </Button>
+        <Button
+          onPress={() => deleteAll()}
+          title="delete everything">
+        </Button>
       </View>
     )
   }
-}
\ No newline at end of file
+}
diff --git a/index.js b/index.js
index f1543b7..408a2f0 100644
--- a/index.js
+++ b/index.js
@@ -1,9 +1,4 @@
 import { AppRegistry } from 'react-native'
-import Home from './app'
-import { openDatabase } from './db'
+import App from './app'
 
-// TODO error handling
-openDatabase()
-  .then(() => {
-    AppRegistry.registerComponent('home', () => Home)
-  })
\ No newline at end of file
+AppRegistry.registerComponent('home', () => App)
\ No newline at end of file
diff --git a/package-lock.json b/package-lock.json
index c531614..21bda8c 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -4693,6 +4693,11 @@
         "merge-stream": "^1.0.1"
       }
     },
+    "js-joda": {
+      "version": "1.8.2",
+      "resolved": "https://registry.npmjs.org/js-joda/-/js-joda-1.8.2.tgz",
+      "integrity": "sha512-3w+3TnKqiplQyG/YQk31cBhJ/sg2Xb/fX7lneiK+z+nEjTzdfvHqJquJhtzyEA1NyLJKNpIeOQSBr3Q4nY+O8Q=="
+    },
     "js-tokens": {
       "version": "3.0.2",
       "resolved": "https://registry.npmjs.org/js-tokens/-/js-tokens-3.0.2.tgz",
diff --git a/package.json b/package.json
index 28310a9..ff64b52 100644
--- a/package.json
+++ b/package.json
@@ -14,6 +14,7 @@
     "lint": "eslint app test"
   },
   "dependencies": {
+    "js-joda": "^1.8.2",
     "moment": "^2.22.1",
     "react": "16.3.1",
     "react-native": "0.55.4",
diff --git a/test/get-cycle-day.spec.js b/test/get-cycle-day.spec.js
index 64ee0b9..60b4fa5 100644
--- a/test/get-cycle-day.spec.js
+++ b/test/get-cycle-day.spec.js
@@ -7,233 +7,126 @@ chai.use(dirtyChai)
 import getCycleDayNumberModule from '../get-cycle-day-number'
 
 describe('getCycleDay', () => {
-  const getCycleDayNumber = getCycleDayNumberModule()
-  it('works if the last data entered is a bleeding day', function () {
-    const cycleDays = [{
-      date: new Date(2018, 5, 2)
-    }, {
-      date: new Date(2018, 5, 3),
+  it('works for a simple example', function () {
+    const bleedingDays = [{
+      date: '2018-05-10',
       bleeding: {
         value: 2
       }
     }, {
-      date: new Date(2018, 5, 4)
-    }, {
-      date: new Date(2018, 5, 9),
+      date: '2018-05-09',
       bleeding: {
         value: 2
       }
     }, {
-      date: new Date(2018, 5, 10),
+      date: '2018-05-03',
       bleeding: {
         value: 2
       }
     }]
-    const targetDate = new Date(2018, 5, 17)
-    const result = getCycleDayNumber(cycleDays, targetDate)
-    expect(result).to.eql(9)
-  })
-
-  it('works if the last data entered is a non-bleeding day', function () {
-    const cycleDays = [{
-      date: new Date(2018, 5, 2)
-    }, {
-      date: new Date(2018, 5, 3),
-      bleeding: {
-        value: 2
-      }
-    }, {
-      date: new Date(2018, 5, 4)
-    }, {
-      date: new Date(2018, 5, 9),
-      bleeding: {
-        value: 2
-      }
-    }, {
-      date: new Date(2018, 5, 10),
-      bleeding: {
-        value: 2
-      }
-    }, {
-      date: new Date(2018, 5, 13)
-    }, {
-      date: new Date(2018, 5, 14)
-    }]
-
-    const targetDate = new Date(2018, 5, 17)
-    const result = getCycleDayNumber(cycleDays, targetDate)
-    expect(result).to.eql(9)
-  })
-
-  it('works if the cycle days are not sorted by date', function () {
-    const cycleDays = [{
-      date: new Date(2018, 5, 13),
-      bleeding: {
-        value: 2
-      }
-    }, {
-      date: new Date(2018, 5, 9),
-      bleeding: {
-        value: 2
-      }
-    }, {
-      date: new Date(2018, 5, 3),
-      bleeding: {
-        value: 2
-      }
-    }, {
-      date: new Date(2018, 5, 4)
-    }, {
-      date: new Date(2018, 5, 10),
-      bleeding: {
-        value: 2
-      }
-    }, {
-      date: new Date(2018, 5, 2)
-    }]
-
-    const targetDate = new Date(2018, 5, 17)
-    const result = getCycleDayNumber(cycleDays, targetDate)
-    expect(result).to.eql(5)
-  })
-
-  it('works when there are only bleeding days', function () {
-    const cycleDays = [{
-      date: new Date(2018, 5, 9),
-      bleeding: {
-        value: 2
-      }
-    }, {
-      date: new Date(2018, 5, 10),
-      bleeding: {
-        value: 2
-      }
-    }]
-    const targetDate = new Date(2018, 5, 17)
-    const result = getCycleDayNumber(cycleDays, targetDate)
+    const getCycleDayNumber = getCycleDayNumberModule(bleedingDays)
+    const targetDate = '2018-05-17'
+    const result = getCycleDayNumber(targetDate)
     expect(result).to.eql(9)
   })
 
   it('works if some bleedings are exluded', function () {
-    const cycleDays = [{
-      date: new Date(2018, 5, 2)
+    const bleedingDays = [{
+      date: '2018-05-10',
+      bleeding: {
+        value: 2,
+        exclude: true
+      }
     }, {
-      date: new Date(2018, 5, 3),
+      date: '2018-05-09',
+      bleeding: {
+        value: 2,
+        exclude: true
+      }
+    }, {
+      date: '2018-05-03',
       bleeding: {
         value: 2
       }
-    }, {
-      date: new Date(2018, 5, 4)
-    }, {
-      date: new Date(2018, 5, 9),
-      bleeding: {
-        value: 2,
-        exclude: true
-      }
-    }, {
-      date: new Date(2018, 5, 10),
-      bleeding: {
-        value: 2,
-        exclude: true
-      }
     }]
-    const targetDate = new Date(2018, 5, 17)
-    const result = getCycleDayNumber(cycleDays, targetDate)
+    const targetDate = '2018-05-17'
+    const getCycleDayNumber = getCycleDayNumberModule(bleedingDays)
+    const result = getCycleDayNumber(targetDate)
     expect(result).to.eql(15)
   })
 
   it('gets the correct number if the target day is not in the current cycle', () => {
-    const cycleDays = [{
-      date: new Date(2018, 5, 14),
-    }, {
-      date: new Date(2018, 5, 13),
+    const bleedingDays = [{
+      date: '2018-05-13',
       bleeding: {
         value: 2
       }
     }, {
-      date: new Date(2018, 4, 12),
-    }, {
-      date: new Date(2018, 4, 11),
+      date: '2018-04-11',
       bleeding: {
         value: 2
       }
     }, {
-      date: new Date(2018, 4, 10),
+      date: '2018-04-10',
       bleeding: {
         value: 2
       }
-    }, {
-      date: new Date(2018, 4, 9),
     }]
 
-    const targetDate = new Date(2018, 4, 27)
-    const result = getCycleDayNumber(cycleDays, targetDate)
+    const targetDate = '2018-04-27'
+    const getCycleDayNumber = getCycleDayNumberModule(bleedingDays)
+    const result = getCycleDayNumber(targetDate)
     expect(result).to.eql(18)
   })
 })
 
 describe('getCycleDay returns null', () => {
-  const getCycleDayNumber = getCycleDayNumberModule()
   it('if there are no bleeding days', function () {
-    const cycleDays = [{
-      date: new Date(2018, 5, 2)
-    }, {
-      date: new Date(2018, 5, 4)
-    }, {
-      date: new Date(2018, 5, 9),
-    }, {
-      date: new Date(2018, 5, 10),
-    }]
-    const targetDate = new Date(2018, 5, 17)
-    const result = getCycleDayNumber(cycleDays, targetDate)
-    expect(result).to.be.null()
-  })
-
-  it('if there are no cycle days', function () {
-    const cycleDays = []
-    const targetDate = new Date(2018, 5, 17)
-    const result = getCycleDayNumber(cycleDays, targetDate)
+    const bleedingDays = []
+    const targetDate = '2018-05-17'
+    const getCycleDayNumber = getCycleDayNumberModule(bleedingDays)
+    const result = getCycleDayNumber(targetDate)
     expect(result).to.be.null()
   })
 })
 
 describe('getCycleDay with cycle thresholds', () => {
-  const getCycleDayNumber = getCycleDayNumberModule({
-    minCycleLengthInDays: 5
-  })
+  const opts = { maxBreakInBleeding: 3 }
 
-  it('disregards bleeding breaks shorter than the min cycle threshold in a bleeding period', () => {
-    const cycleDays = [{
-      date: new Date(2018, 5, 10),
+  it('disregards bleeding breaks shorter than max allowed bleeding break in a bleeding period', () => {
+    const bleedingDays = [{
+      date: '2018-05-14',
       bleeding: {
         value: 2
       }
     }, {
-      date: new Date(2018, 5, 14),
+      date: '2018-05-10',
       bleeding: {
         value: 2
       }
     }]
 
-    const targetDate = new Date(2018, 5, 17)
-    const result = getCycleDayNumber(cycleDays, targetDate)
+    const targetDate = '2018-05-17'
+    const getCycleDayNumber = getCycleDayNumberModule(bleedingDays, opts)
+    const result = getCycleDayNumber(targetDate)
     expect(result).to.eql(8)
   })
 
-  it('counts bleeding breaks longer than the min cycle threshold in a bleeding period', () => {
-    const cycleDays = [{
-      date: new Date(2018, 5, 9),
+  it('counts bleeding breaks longer than maxAllowedBleedingBreak in a bleeding period', () => {
+    const bleedingDays = [{
+      date: '2018-05-14',
       bleeding: {
         value: 2
       }
     }, {
-      date: new Date(2018, 5, 14),
+      date: '2018-05-09',
       bleeding: {
         value: 2
       }
     }]
-    const targetDate = new Date(2018, 5, 17)
-    const result = getCycleDayNumber(cycleDays, targetDate)
+    const targetDate = '2018-05-17'
+    const getCycleDayNumber = getCycleDayNumberModule(bleedingDays, opts)
+    const result = getCycleDayNumber(targetDate)
     expect(result).to.eql(4)
   })
 })
\ No newline at end of file