Anal??!

So me and my bf were having sex and I had my legs up in the air and he was holding my ankles. His penis slipped out and when he put it back in it felt wrong and hurt so he stopped and I said "did your dick go in my butt!?" And he said that he didn't think so because it didn't feel different and he thinks anal would feel different (we've never tried it). So we continued having sex but my butt hurt but my vagina felt good ;). So I'm on my period and I was totally relaxed so could it be possible it went it my butt or could it just be the angle?? My butt doesn't hurt anymore it just feels like I have to poop lol. Also, after sex my hands kinda smelt like poop. I feel like anal would hurt more because it didn't hurt that bad.