FERTILITY TRACKER PROBLEMS

Jemina

I have my Flo app for more than a year now to track my cycle, and this month of August my husband and I decided to conceive after my last period which is on July 26 and ended on July 29. And this Flo app said that my fertile days starts on August 1 - 10.

But in other hand, I decided to download other app which is this app 🤗 but when I logged my first day of my last period it gave me different fertile days 😭 Which one is true???