did I cum or he did? HELPPPP

So, I just started being "sexually active" since I met my boyfriend, which is why I don't know much about sex. The thing is that, last month, after he came, he pulled his penis out but the condom kind of got stuck inside. I took it out, and went to the bathroom to pee, and when I cleaned myself, I noticed a good amount of cum on the paper. I don't know if it was mine or not, and I'm worried because I don't take any birth control. Another thing is that I'm supposed to get my period tomorrow, and I'm usually spotting around 2 days before getting my period, which hasnt happened. I've been feeling nauseous for the past week but not sure if its because I'm so worried about it. Help meeeeeee, I tried to google but internet isnt really clear when it comes to this.