Yeah, I get those hopeless, depressed periods too. I think I'm in the middle of one these lowly periods too. I just went through a really depressing past three days full of negative thoughts about school, family life, death, religion... it's so fucked up.
I set up a doctor appointment and I'm going to tell him about my depression and to check if I'm bipolar; those mood swings are unacceptable, they don't seem rational or balanced.