I used to have what are called stress dreams, where I would be in an insolvable puzzle, and when I would solve it my dream would start at the beginning. Honestly I didn't get much sleep because of it so I had to learn to lucid dream.
I need to find my old dream journal, my dreams were so messed up. I dreamed ( is that even a word?) of neonazi's invading and taking over America once. In that dream I was actually shot execution style in the head, died, and didn't wake up right away... very interesting being in darkness, feeling like you are floating and laying in fetal position.