I’m confused.

So my boyfriend and I have unprotected sex a lot but we always go until he feels like he’s gunna cum soon, and then I give him oral until he eventually does cum, im not on pills and we don’t usually lose a condom, but this app says I’m 4 days late on my period(but it could be wrong because I only made an account yesterday) and my other app that I’ve had for a while says I’m supposed to start today, I haven’t started yet but i might start later?

Any tips or info?