Paralyzed in your sleep??

I know to some this may sound strange - but it happens to me a lot. I wake up and I know what is going on but I can't move. Then it scares me... It started when I was really little and happens a couple of times a month. Most of the time it happens in the middle of the night. It feels like I am laying there forever but I am sure it is just a few seconds. I am going to research it and see why that happens... It's like I am awake but my body is not...

I know... most of you think I have lost my marbles...