I've had this for some time now -- I've thought that maybe it's because I suppress things during the day and then my mind tries to sort through them in dreams, so I wake up feeling so anxious and depressed. I make myself get up and try to go about the day, but then my hands start shaking and it takes a couple hours for that to stop. By the end of the day I'm fairly OK, but really tired so I go to bed much earlier than I used to.