This has happened to me three time in the night. My body feels as if it is vibrating and feeling very heavy.I will also hear a loud noise in my ear as if I can hear my body vibrating. My heart beats really fast and start to feels scared. I think I also lose feeling like I have a heavy blanket on top of me but when this happens I can't even feel the blanket. The last time this happened I tried speaking out But no sound came. This is very frightening each time.