Situation won't leave my mind and I can't tell if it was sexual assault

I became friends with this guy and he was immediately creepy towards me. He made the conversation sexual and I was very uncomfortable, but I laughed it off and acted like it was fine.

I ended up friendzoning him a few days later, and he went on to hate me and talk shit about me to everyone (he was one of those creepy entitled guys).

A long time after this, we end up being friends again. I did genuinely enjoy hanging out with him because we had the same sense of humor and I barely had any other friends at the time.

He quickly made advances towards me like asking to kiss me (I laughed in his face) and making it clear he wanted to hook up with me. I thought I made it really clear I wasn't interested. I even remember saying I wasn't gonna get involved with men for a long time.

Then one day we got drunk together, and somehow we ended up hooking up. I remember thinking in the moment that I would NOT be doing that if I were sober. Honestly I don't know why I did it.

I don't like thinking about that time and having to realize that my boundaries weren't respected at all.

Something that also pisses me off is that I've asked him about that day, and he literally doesn't even remember it. That's how unimportant it was to him. Meanwhile, it was a huge thing that weighed on my mind.

What are your opinions?