I Am Scared of Relationships

I can't get this off my mind and it's driving me nuts. I'm pretty sure I like this guy. It was a few nights before my 21st birthday. He wanted to see me drunk and said I should stay at his house and we could drink. I ended up doing it. At first, I was nervous, but I ended up drinking with him. It was kinda funny for awhile and then I ended up having a panic attack. The shows we were watching got to me. I told him about stuff that happened when I was little and he was comforting. He slept next to me that night, holding me so I wouldn't hurt myself. I felt so safe laying with him and I felt like he cared, but I was too afraid to do anything. I pretended like I didn't remember what happened in the morning. I wanted to cuddle next to him the next time I saw him, but I was too scared. Now it's been months since then and he has a girlfriend. I'm really jealous of her and want to be alone with him. Not necessarily to do anything, just to talk. I feel so guilty. I wish I would have done something awhile ago, but I was too scared. I'm to scared to tell anybody about that night with him and that I like him.