Sleep, damn you! Sleep!

I've been operating on six hours a sleep a night all week. Since today is Saturday, I planned on sleeping in. Do I have to tell you that my plan didn't work out? I ended up waking up at six and then not being able to get back to sleep. Hell, even on school days I don't have to get up at six. Eventually, I got back to sleep, but only after lying there wide awake for over an hour. Why won't my miserable body cooperate? By three o'clock I'll be yawning like crazy.