Sleep paralysis is being in a situation where you felt like you were awake but yet were unable to move. Sleep paralysis may leave you feeling afraid, mainly if you also see and/or hear things that aren't really there.
Your body slowly relaxes while you’re falling asleep and more often than not you become less aware, so you don’t notice the change. However, if you remain or become aware while falling asleep, you may notice that you can’t speak or even move.