You're not.

I've always been pretty much alone. I don't make friends often, and when I do, I often fail to maintain the friendship. It usually doesn't bother me much. When I'm having a depressive episode, though, it hurts. The loneliness literally starts to hurt.

I wonder if it has something to do with feeling vulnerable. After all, when one is ill (mentally or physically), that is when they need those they care about the most.