I regret it 🙄

Last night I hung out with a guy I had been talking to for about 2 months and we drank a little and end up having sex. I regret it and I'm literally beating myself up over it because I told myself that I wouldn't give it up to him because he has sex with other females as well. But obviously I didn't stick to my word. Should I feel bad? Or should I just let it go and never do something like that again?! Which I won't but I just feel terrible. Don't really know how I should feel. And we've hung out a lot before and he knows sex was out of the picture. We had drinks yesterday that he bought and obviously he didn't force me to drink but I did and I feel like he took advantage of me being drunk. Because he knew he wouldn't get it while I was sober. Do I have any right to feel that way?!