Two totally different peak days?? Glow come on dude...

So my last period was 6/7 and according to the app my most fertile day was the 21st and my period due the 5th. Well, my husband and I are desperate to have a baby and we had a lot of sex around this date...now with no data entered It is now saying I was most fertile on the 24th and my period is due the 8th?!?!? This is a rainbow baby we are trying for and I am beside myself. Could this be an error?