22 Year old, my life should be great, but I am terribly miserable?

I am 22 years old, dual major in college (Economics and Marketing), I have been accepted into numerous law school next year, some with full scholarships. I have dated many girls and have a great girlfriend now who goes to a college near me. However, I feel miserable and I have no friends. I rushed for fraternities at the beginning of my freshman year and got a ton of bids and became president of my pledge cl, however, after a month my pledge cl and I were not meshing well and I left. Throughout the rest of college i have not had very many friends and I spend most nights alone in my apartment. I also live alone without any roommates as I had no one who wanted to live with me. I good at sports, dress well, have nice things etc. but I just do not seem to mesh well with anyone and I do not enjoy going out to crowded places like bars etc. I am very lonely and very miserable and I am not sure why? I suppose I should be happy, but I do not like the kids that I am around and I do not meet many kids who I enjoy spending time with. Am I depressed? Does anyone have any ideas? My family does pressure me a lot and I do feel like a failure most of the time.