I once woke up in the middle of the night and had sleep paralysis, which as other people would described it, was loving scary as hell.
I couldn't move or talk, anything below my head, I couldn't feel.
I was hallucinating, seeing shadows in the hallways that I know weren't there.
My heart was beating insanely fast, at first I thought I was having a heart attack.
I was filled with this irrational fear, I knew what was happening, and that I was safe, but I was still stricken with this odd horror, that made me sweat and almost cry.
TL;DR: forget sleep paralysis.