Fear not, their are two common reasons for this.
1, App recently updated
In some rare cases the logs no longer display after updating to the latest version. This is a one-time issue and once corrected should not happen again.
- Double tap your iPhone's/iPad's home button
- Flick Baby Feed Timer off the top of the screen to force close it
- Open Baby Feed Timer again and all your logs should now be there again.
2, Accidentally registering a second child
- On the timer screen there is section at the top with your baby's details. If you try swiping this to the left or right you will probably see that there is another child's details registered.
- Once you switch back to your actual child's details you will see all your data again.