What did you eat before you went to bed?
I've had a few memorable dreams. When I was in college I lived in a 2nd floor apartment and my bedroom window overlooked the sidewalk. I had a nightmare that there was a dragon under the bed and he was swinging his tail back and forth, scraping it against the floor. When I woke up I realized it was the landlord outside shoveling snow off the sidewalk. Scrape, scrape, scrape...
After I graduated I had a recurring dream that they discovered I had one more course to take before I could get my diploma. This went on for a couple of years after I actually got the diploma.
Before I started using the CPAP I had almost nightly dreams that I could not sleep. I dreamed I was awake tossing and turning and was very upset that I could not get to sleep. But I would wake up and look at the clock and realize two-three hours had inexplicably passed. As soon as I got the CPAP these dreams went away.