RC, perhaps it would help if you sought out some counseling. I don't mean that something is wrong with you. I do think that perhaps it might help you to talk it through with someone who could give you an honest assessment of how you come across.
Many years ago my husband's office brought in an expert to help the employees see themselves as others saw them. They chose some kind of exercise and videotaped each employee. Then they played back the video to each person to work with them on how to do a better job. When one man saw his video, he cried. He had no idea how he presented himself to others. It was hard on him, but they worked with him for a while (the company took care of the expense) and it really helped him.
This is different than what you are talking about, obviously, but I think that you could possibly use it as a springboard in talking to a counselor about ways to help you be more successful in reaching out to others.
Knowing WHO to reach out to and who not to is half the battle. I do still have college friends who I'm close to, but they live far away and we don't see each other often. Outside of college friends, I have lived in many different places, and wherever I live, I try to meet new people. Some "friends" stick and some don't. Sometimes it is me who drops out and sometimes it's them. The old adage "Make new friends and keep the old ones - one is silver and the other gold" is something I work hard to do. Even on the other side of the world we are able to keep our friendships alive and that means a great deal to me.
The thing that I have found that works is to show my friends that I care about them. Paying attention to what is going on with them, remembering what they've told me before (harder now that I'm older, ha ha!) so that I don't appear to be clueless, being able to listen and be empathetic helps. Certain personality types appeal to me over others, but I do have different types of friends. It's just that those who are outgoing are easier for me to stay friends with. It's like we feed off of each other's energy.
I think that trying to think positively makes a big difference too. Negative thinking comes across loud and clear, and that makes people uncomfortable. Trying hard to be positive makes it easier to have friends. Not being critical of friends, picking on every little thing they do because I wouldn't do something the way they do, also helps. I know people who find fault with everyone around them. It's amazing to me that they have ANY friends, thinking that poorly of people they claim to like.
The last thing that I would offer is to try to find the BEST in yourself and have confidence in it. People like being around a confident person. That helps make and keep friends.
Don't give up - just try to find someone to help you find a new way to approach it. Unless you actually LIKE being alone, you shouldn't settle for it.
D.