Search Results: shy or uninterested

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