The others have given you a lot of wisdom. You may be brighter than you think you are. Perhaps you could take a community college class to convince yourself and to practice meeting people of similar interests.. You must have more going for you than you think. That these people have tried so hard to stay in touch says you may be more a friend than you think. You offer something they need. So many of us walk around exuding conficence and surity, while inside we are afraid the world will see we are frauds.
Vulgerrlove speaks the truth. I only recently broke the chains which were holding me prisoner, and it was terrifying, still is. The first time I went to a new church, as the new me, I froze to the car. I couldn't move, the world swam around my head, and I wanted to throw up. But I did it. I went into the church, and it was easier the next time. You are not a freak. We all are unique. Positive thinking may not always work, but it can surprise you.
Columnist Mike Roiko once observed that we often mistake aquaintances for friends. If we have had enough friends to fill the fingers of one hand when we die, we are more futunate than most. Go get em tiger!