I thought a bit about your problem, and the main essence of it all is that if you want to feel like a member of the group involve yourself. I have a very silent yet kind friend, that never says anything. It can be really annoying, and sometimes I do not want to hang out with her at school because of the fact that she does not involve herself. Sometimes it feels like
she just wants someone to spend time with at school, so others will not think at here as an "outsider."
I got really annoyed of this before, and as the spambear I am, I always talk a lot around her. (Mostly about things that have no meaning at all.) I am just trying to fill the gap, but it does not seem to work. And what do I do? I run away, I just do not want to hang around someone like that. It is like she just do not want to be an outsider.
So this is what I think your problem is all about; confidence. You need the confidence to get out there, share your meanings and get new friends. It is possible that your friends are tired and bored of you; you need to go for it! It is not necessarily the world that needs to change, it could be you. I do not have one or two best friends, but I have a lot of friends. When I am able to just hang out with them, without doing or saying anything then I know that I am comfortable around them.
You say that you get along with your friends just fine, but are you sure about that? Have you ever considered trying to make some new friends? Change is sometimes very good, and I think that would be good for you. When your friends are running away you have two options; get involved or make some new friends.
So get out there, and good luck!