Late period, negative test

Help please,

My period is never late, I’ve been using the eve app since 2015 and I’ve never been late.

My period is 10 days late. I have sex 5 days before my period was due, so wasn’t trying to get pregnant and before that. I was in lockdown for 4 months so I couldn’t have gotten pregnant any time before that.

I’ve been getting cramps almost everyday, and I’m randomly constipated and really gassy. Surely you can’t get pregnant right before your period right? And he didn’t nut in me (I know pre cum is a thing) but this is all just really weird. I’m convinced I’m dying lol