Does anyone ever feel that some type of force is holding you down in the morning and you cant move??

This sounds really weird but it has happened more than once in like a few months. Im waking up usually from a bad dream and when I try to get up I can't nor can I yell. Its just a terrible feeling. I've had really weird dreams like of relatives being eaten by crocodiles. NO, I havent watched any scary movies lately so that cant be it.