OK, this will sound weird, but whenever I am depressed for some reason, I usually just act tired and, well, depressed. But here's the scary part, after about an hour of being depressed (and I'm not always sure what about) I get really angry. Just genuinely pissed off, at people who I know have done nothing to upset me, but I just feel angry. And then, after being angry and irritable, it'll all clear up, like nothing ever happened. Depression turns into anger, which then disappears. Wow, this really sounds crazy... I better stop now.