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. Sleepers often wake up confused, or just don't make any sense which is called "hypnopompic speech".
The good news is sleep paralysis is not considered a dangerous health problem. Sleep researchers conclude that, in most cases that sleep paralysis is simply a sign that your body is not moving easily through the stages of sleep. Rarely is sleep paralysis linked to deep underlying psychiatric problems.