The experiences of not recalling bits and pieces of our lives can elicit high anxiety, for sure.
You have written: "Wow! You guys make it sound like most guys would take advantage of a drunk girl!"
I have read through the posts and I do not find anyone stating or implying this. You are the only person questioning the guy's intentions.
Your account paints this young man in a very positive light. I think I would settle with that, if it were me, unless I had different information.
I just want to mention, and I am not implying anything about you: It is possible he, too, was blacked out. There is this idea that if two people are drinking heavily and there is some sexual activity, the male is taking advantage of the female. This may be true in some cases; however, it is not always the truth. I have known many females who often make the first move and/or work to seduce the male. In all fairness to the topic, I'd like to just point out what other posters have pointed out: When we drink to the point of blacking out, we cannot know what, exactly, has transpired. Again, I am not implying anything about you. I am stating this for all of us.
We'd all be wise to at least consider the possible interactions of our meds with alcohol and/or any recreational drug.
I will share this with you: I recall attending a large party one holiday season, probably 30 years ago. I was on an AP med. I am not a drinker anyway. I have maybe two drinks a year. My BIL went to the bar and brought back a drink, insisting I at least sip on it. Everyone around me was hounding me to drink, as they knew I do not care to drink. I did sip a little, it really did not taste good to me at all. The next thing I know, it is the next morning. I wake up in my own bed and was shocked because I have no idea as to what had happened! I was with family and they made sure I made it home safely, thankfully. They had no idea I had blacked out. None. How does anyone else tell when someone is blacked out? It is easy to tell if someone is passed out, but "blacked out?" I do not think so.
In your case:
I am sorry for any anxiety you are experiencing and I hope you can work your way through this.

I wonder why this memory has come up now? You mention having watched a movie. Can you pinpoint something in the movie which may have reminded you of this life experience? Please do not feel like you have to share that info here.

Just something for you to possibly consider?
If you memories are positive, you were feeling comfortable, etc,, then great!

If you are wondering if there is more to the story, just remain open-minded and see what, if anything else, surfaces. I agree with bpcyclist, if this continues to bother you, please do work through this with you therapist?
You seem angry/upset toward the end of your original post? Are you angry with yourself?
As Christina has mentioned, many of the BP meds do not mix well with alcohol. I am guessing someone might very well blackout sooner if taking an AP and alcohol together.. It was certainly true for me in the example I have shared.
I want to thank you for the reminder to all of us to take good care of ourselves by making wise decisions in every setting. In some cases, we might decide to not get into certain types of environments, situations. We are each responsible for our choices/decisions.
Again, giddykitty, I do hope you will resolve any/all you need to resolve in perfect timing. I do know what it is like to blackout; it made such an impression upon me, I still recall that experience as though it has just happened. It's unnerving to say the least. Please do pursue this experience with your therapist, especially if this continues to bother you. Thanks so much for sharing your story.
Much Love