Have you considered that if you were vomiting from the effects of the alcohol, that could cause pressure at lead to this problem?
Same thing happened to me when I got drunk and stayed on my boyfriends couch without him knowing.. I woke up with a bad hemmoroid and thought I was also raped in my sleep. He came home and was found sleeping in his room. But I read online, where drinking alcohol heavily the night before can also cause this to happen. Inwas just as surprised tho that the hemmoroid was so big and painful for days. Mine sounds just as bad as yours so that is good for me to know, and now I don't think I was raped but just coincidence.. unless, when you went to sleep.. there was people who practice anal sex present before you went to sleep .. Then if there was then I did read somewhere you can be raped in your sleep and somtimes without alcohol so if there people possibilities present then I would be back on the suspecting side. Otherwise, it was heavily drinking alcohol with little hydration and it caused a severe flare up.. One time, I swore my ex was invlolved with roofying me as well while I was at a pride philly event so I wouldn't be surprised of they were both true.. he was so untrustworthy. But I have no proof so as it stands, the hemmoroid was from drinking heavily. And I was not roofied.. ever happens again tho.. I'm going to the hospital for a check up and blood test and you should too.. If you ever suspect you were raped, take it seriously. Nobody has the right to violate a person like that non-consensually, partner or not. Hope that helped cause I have had the same question before. And I am male for your information.
Hemorrhoids can, indeed, cause bleeding. Were you in a situation in which a rape may have occurred? If so, and you believe that this is a real possibility, you should schedule an appointment with your doctor to receive proper HIV/STI testing and to check for anal trauma.