Ashamed and guilty

I went on a date with a guy I really liked but said he wasn't interested in getting into a relationship right now. I got so drunk that we had sex (without protection so I took plan b) but I regret it so much because I just feel used but I was so drunk I don't even remember making a decision and it sucks and I feel dirty and gross and embarrassed..help please I'm finding it hard to get though every moment