yea sleep paralysis can be creepy indeed, though I hear its far more likely to occur when sleeping on your back.

One experiece I had was very similar except a hooded figure at the door was talking to me, although it was terrifying after realising i could not move i somehow managed to calm down and drift into sleep again after telling the figure to please go away.
It seems strange to me that the entity associated with sleep paralysis is almost always seen as negative and scary and many people have very similar descriptions..