chemical pregnancy or period?

okay so my boyfriend and i had sex about 3 weeks ago and the condom did rip, we stopped immediately right after but i knew there could’ve been a chance that i could get pregnant... so i’m supposed to start my period tomorrow but got it today and my period is extremely heavy, way more than usual. I also experience EXTREMELY painful cramps to the point where i would wake up in the night because of them and i’ve had cramps but not this terrible. I have been feeling dizzy and nauseous but i thought it was because i was near my period but today i got a weird clot of blood and i instantly felt that something was wrong. Am i just overthinking and it’s just my period or could i possible had a chemical pregnancy?