What’s wrong with me?

So today my boyfriend and I showered together. I’ve never had sex, but today we got close. He basically humped me from the back and his dick went like through my ass but it didn’t go into a hole. Maybe once or twice his dick actually went into my ass and it hurt a bit. Now after about 3 hours my asshole really burns and my vagina feels really sensitive. I did not pee immediately after this.. I don’t know if I feel pain just bc like something LITERALLY went into my ass (only like 1cm) and it could be inflamed or something bc like anal is painful obviously, but I just want to know what I should do. I’m going to the gynecologist on Thursday, but I’d REALLY rather not talk about this in front of my mother. Please help? Why does my asshole burn and how can I prevent this?