am i pregnant?

ive never tracked my period before i just got this app for but im just very confused

we are both virgins and the other day had sort of sex? he inserted himself and i got on top of him but when we realized we had no condoms and that we were being up protected we stopped immediately. neither of us came although we did end up pleasing eachother and coming later on. 2 days before that while i was giving him a handjob and he came on my inner thigh

the morning after he inserted himself i got my period but it was a bit different then my usual period like very heavy the first day and then very very light the rest of the days

and now i feel alot of fatigue, nausea and headaches im just very scared because i cannot risk pregnancy at all at the moment

i dont know who to ask since we were both virgin and barely know anything lol

help?