Search Results: start talking to this guy on facebook

Last semester (Fall 2016), there was a guy in one of my classes I was interested in, although I had never talked to him. I would catch him watching me throughout the semester but am also not really sure if maybe he was just looking my way and wasn't really looking at me.

On the last day of class he turned around and started talking to me out of the blue. It completely freaked me out because, 1) I really hoped he would talk to me before the semester ended and 2) I'm extremely shy. But instead of taking advantage of the situation, I shut down and came off as really standoff-ish. The professor announced that we had to take the final and he had to stop conversation. He never introduced himself nor did I. I would like to think he was trying to get to know me right before the semester ended, but I really don't know what his intentions were.

I feel horrible because I might have passed up a really good thing, but also because I think I might have come off as downright rude and uninterested. It was a fairly small class, so I knew his name and I think he probably knew mine. I found him on facebook and don't know what to do. Add him, send him a message? I'm scared of coming off as creepy but also scared I might regret it if I never try. We have no mutual friends. The last day of class was early December, so it's been a few months. Would it be just a little creepy or super creepy? Will a message explaining myself make it a little less creepy?

*Also, I don't go to the same school anymore but I am still in the same city. So, running into him on campus is not a possibility. We also have no mutual friends

Date 1: You go bowling. You start teasingly joke how you will beat him in bowling, you catch him rolling his eyes. He says he thought you would be shorter in person.
Date 2: He's late to your date by 1 hour due to him burning his foot and him being drunk last night.
Date 3: He takes you to a carnival type thing, wins you a pikachu. Then invites his friends after. You tell him you don't feel comfortable meeting them yet but he insist they come.
Date 4: Before the date, he asks you to be his girlfriend while drunk. He's still on the dating website. When you ask why, he says he still wanted to see who he would match with. Tells you he's falling for you hard and he might love you.
Relationship 1: He tells you he's been to jail and has a DUI. He starts touching you and you tell him it's okay for him to do this. He says, I'll touch you there if I want. You guys try to talk a lot on the phone but he ignores/ hangs up while playing computer games.
Realtionship 2: He's constantly drunk and when you bring up something, he hits your car window in frustration. He tells you you're bullshit in a jokingly way due to winning a game. In front of his friends he told you to get your ass back on the game. You noticed he has puke spots from 3 days ago still on his bed from a few days ago.
Relationship 3: He has a picture of a girl he used to have a fling with in his phone recently and says he only hung out with her to make sure she didn't get taken advantaged of and r*ped. He NEVER likes any of your posts on facebook... But he's constantly like another girls stuff. Everything she posts. When you ask him why, he says he doesn't like pictures or go on social media a lot but he's ALWAYS on there.
Realtionship 4: Unknown best friend who is a girl you never met emerges and he starts talking to her a lot.