Extremely Vivid dreams I have

Ok, as a younger child (4-8 years old) I had these nightmares EVERY night. They were about these cartoonish green people that had long sharp noses and wore this t-shirt I used to wear to bed. The dreams would start out the same every night, just like a movie. One of the "green guys" faces would appear and circle would go around his face. Then spotlights would show and all of the different "characters" of the green guys would be hanging around the spotlights and illegible credits would show up. Then the dream would start with me in some random place, and then the green guy's would show up and do things to me along the lines of mischevious torture. They would pinch me, kill member's of my family, kidnap me, stuff like that. Some times these dreams were so vivid when I woke up from the dream I would be on the other side of the house in the middle of the floor. One of the dreams once ended with me under the computer desk, and when I woke up I was under my computer desk. So these dreams were so real it seemed I would act them out in my sleep.

I also have dreams where I punch myself or choke myself while I am asleep. I once had a dream I was playing catch with this kid at night time, so I couldn't see the ball. Then he threw a rock and it hit my face in the dream, and I woke up and instantly punched myself in the face. I also had a dream once where I was taking a bath and I all of a sudden couldn't move. A little man about 3 inches tall crawled out of the drain and walked up to my neck and started choking me. I woke up a short moment later and was choking myself to the point where I couldn't breathe.

Could someone please explain these to me and why they might be happening?