Yah, that's annoying, because you are then fully awake, with your heart pounding, and it takes another half-hour to get to sleep.
Anyways, the only nightmare I can remember went something like this:
I woke up in the morning, on the day of an exam. I was already late, so I jumped out of bed and walked quickly for the door to go have a shower. Just before I reached the door, I "woke up" again, laying in my bed like I did the first time. This time, I figured that I was actually awake, because I had "woken up" from that weird dream. However, this was not the case. I got out of my bed, and I noticed that I was moving slower. I didn't think much of it, but when I got about halfway across my room, I "woke up" again. This time, I could hardly move at all, and it took all my strength to just get out of the bed, at which time I "woke up" yet again. By now, I was quite frightened, because I thought I was being paralyzed or something. Anyways, this time, all I could do was move my one arm a little bit so I pushed myself out of the bed and fell on the floor. But guess what? Just before I hit the floor, I "woke up" AGAIN. This time, I couldn't move at all. I lay there, petrified (haha, I made a pun), for a while, and could not move no matter how hard I tried.
Anyways, then I woke up for real, forgot about the dream, and went and wrote my exam (and aced it). I told my dad about the dream that I had, and he said that sometimes you get dreams like that the night before you have to do something important that you are anxious about.
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"May your gravity well be shallow, and your deBroglie wavelength short."