TIFU I thought my date cheated on me

So this story happened like 2-3 years ago. everytime i tell this story to friends or at a party it always makes people laugh like hyenas, so i thought you might like it as well... Enjoy

I'm a 20 year old, and I just found a girl that I really liked. We met a night at random by chance and exchanged numbers. I asked her a few days later and we went on our first date. It went better than any other date I've ever been to. She told me about her school and that she had a roommate because she was in college and that I would meet another day. She was absolutely perfect and I really do not want to fuck anything up. It takes about a week and we have both been pretty flooded with work, but we were planning to do some fun Friday night. We go out for dinner, go to an outdoor concert, and then meet some of our friends at a local bar. Things get a little fuzzy from here. We had both been drinking for a while, and so I approach the point where memory is failing and the alcohol takes control. We go back to her college and fall asleep. I get up and go to the bathroom naked and go back to the room. Without believing it would ever happen to me, there's another guy in bed with her. I'm flipping out and my heart is sitting all the way up in my throat. Standing in front of the bed, I try to figure out where this guy came from. I was thinking like, "She lied and fucking lays there hugging him in her sleep? - What the heck !?" I decided that the best action would be to wake her and confront her about it. So I go and wake her up and started asking questions. She completely ignores me and walks into the bathroom. I'm totally speechless, and just want to shout and scream at her. I thought I just had to get some clothes on ( I WAS TOTALLY NAKED) and leave and never come back. While in the bathroom, I'm looking around to find my clothes that I can not find. She comes back from the bathroom and just starts shouting and cursing me out. She started shouting and insisted on knowing who I was and that I had to "Get the fuck out of the room." It turns out that it was not my date at all... but it was her roomate and her boyfriend sleeping. (It was like a big room that's only divided in two by a little line of closets, so i must have confused myself and went to the wrong side of the room) I stood there completely paralyzed, still naked, and embarrassed i started to realize what just happened so i went in to my date. I tried to wake her up, but she was PASSED OUT and slept like a rock. I was exhausted and there was no way I could come home so I decided to lay down again and worry about it the following day. I woke up later around 6 o'clock in the morning, just rushed out and the following texts with her was soo awkward, and we never really talked other than a couple of texts or snapchats which was sad but it was too embarrasing to see her after all of that! :/

TL;DR Thought my date cheated on me. got angry and woke her up. It wasn't her, but her roomate