TTC confusion

So my last period was September 9th and ended the 16th. I got a new phone and had to hand add my period log into my new phone and for some reason it had 2 different prediction dates one said i was supposed to start on the 1st of October and the other one said the 7th but either way i took a pregnancy test around September 29th or 30th it said negative and i still haven’t gotten my period and im past both dates. Any thoughts?