Am I gay/bisexual?

Today I had sex for the second time with a guy and it ended the same way. With him cumming in my ass and then me not only losing interest, but feeling disgusted with myself. Over the years I have watched many gay porn videos, read many gay sex stories, and have gotten off on people talking dirty to me over chat sites. But whenever I finish I find myself feeling very disinterested with what I'm watching and feel more like getting off to girls. Each time while I was driving to get fucked I kept feeling a lack of interest like I didn't want to get fucked. I wasn't nervous I just didn't want to do it even though I went through with it. I also don't like making out with guys and while I was getting pounded I noticed my dick was getting smaller as he continued to fuck me, and now I don't know what I am.