Cried after anal sex but not because it hurt

Me and this guy that I’ve been seeing tried anal for the first time yesterday. It was totally consensual, I was down to try it. I asked him if he would stop if I told him to stop and he said yes. And after three seconds and hurt really bad I told him to stop.

Then I went to the bathroom and like totally lost it. Cried and sobbed. I’m not sure why, maybe because I was surprised how much it hurt, or like I felt like it was for him and not me. I’m not sure. Something about it really affected me and we’ve been weird since then. I was trying to hide my tears from him but he caught on and seemed a little upset that I was crying. I couldn’t tell him why because I don’t even know myself.