I feel compelled to say that the op went through a couple of similar instances when she was younger, so while she is bravely shouldering the responsibility for this, I personally feel that even if she were conscious at the time she probably wouldn't have been able to move for fear.
iit I really hope you don't mind me saying what I've said BUT I feel it's important that people don't see this as you making excuses for getting a bit too tipsy and falling into bed with someone else, because the more it plays on my mind the more I think it wasn't your fault and it probably wasn't consensual at all.
I know you don't want to call it rape and it's no surprise considering what you've been through, but you are shouldering something and being made to deal with something REALLY BLOODY HARD all alone when it seems like you really shouldn't have to.
This is such a grey area I can't give advice on what you should do. Sometimes the right thing to do isn't the BEST thing to do for you. If you are getting/due to be getting help with other issues you have going on, can you speak to that professional person about this situation first? as it's more pressing.
If there's anything I can do to help, let me know. But please don't be too hard on yourself, and don't be pressured into any decision. I hope you have someone you can confide in in real life, who can give you a real hug, but for now from me.