I'm pretty much the same, the only two friends I have are not really available to hang out or share much since one moved abroad recently and one is in a new relationship.
I've always been the friendless one, always on the edge of any circle/group, never the one in a relationship, etc.
It's incredibly lonely and most people can't truly understand how truly unhealthy and painful it is to be this way.

I also think it's like a vicious circle because without friends it's hard to make other friends, both cause you generally meet people through other connections ,and also because you just don't get much of the experience that helps with making good connections.