what's this?

What's wrong with me these days! I really can't understand my behaviour. One moment I am glad the next moment I am sad. Why? I really don't know what happened. Depressed? I easily get irritated with things. And I don't even want to have a conversation with other people except to my bestfriend. I feel deserted and betrayed and used and dumped. Aggghhhhhhhhh! What this? Am I losing my sanity? Is this normal?