I'm pretty sure its a form of depression. I have something similar.
Every so often I get this weird feeling like my friends are ignoring me or I feeling like I'm annoying everyone. I get really quiet and just don't have the energy to do anything. If I'm with a group of friends I pretty much separate from them just because the feeling makes me not want to talk to anyone. It makes me feel really distant from everyone and it gives me the feeling of desertion by my friends. Its terrible.
Then it goes away in about an hour and everything goes back to normal.