sex right before period? could i be pregnant?

it was sunday early morning at like 3am when i went to this guy's house and we got drunk and high and made out a lot. we eventually got naked you know, and he wanted to see how tight i was, so i let him go in for a little bit but my period was just beginning and he didn't have a condom on and pre-cum is a thing... then later that day my period came as usual (i had spotting that saturday evening before i went to his house so i was already on it). but last night i masterbated and my period kinda slowed down. is that normal? could i be pregnant? i'm really fucking worried.