I go for days on end with just cat naps or if I'm lucky, 4 hours at night of sleep. Then one day I will sleep a solid 12 to 16 hours. This just started happening recently. While I am grateful for the rest I can't control when it's going to happen and yesterday we had planned on finishing our Christmas shopping and I slept all day until 1:30am this morning. I even have prescription sleeping pills, but they just make me loopy, not sleepy.