angel, I'm sorry it took so long for me to reply to this. It was one of those posts where there was so much I wanted to say, I couldn't figure out how to reply without writing a novel.
I am also one of those "overlooked" people, that never seems to be on the receiving end, and my T and I have been working on this issue. One of the things she is always suggesting is that the reason people don't consider me, or give back to me, is because I don't convey that I need anything. So, she says that if I want something, I should ask for it. And you know, it works. I ask people specifically to let me know if they are going out or something, I'll ask people to call...I even asked for a birthday party. I'll admit, it would be nice if I wouldn't have to ask, but it sure beats not asking and getting nothing.
I have found that finding friends can be a matter of luck as much as anything. I spent much of my life in the same situation you describe...being friendly with someone for a short time, but always drifting apart. But then I was fortunate to meet someone who has really stuck around through a lot...she and I have been friends for over 20 years now. I hope you don't give up on meeting new friends, because the next one you meet might be that wonderful person who will stick with you through everything.
*hugs*
mj