Been having this for a few years now, must have it at least once a month one of the worst dreams and feelings ive ever had.
I tend to have this dream when i am really tired. basically i will be asleep in my bed but in my dream i feel as if i am awake in my bed paralysed (as if my body has shut down but i am still concious)with people or some sort of things in my room but for some reason my vision is blurred and i can only see shadows. The worst thing about this dream is that i feel as if im about to be attacked and i try and shout for help but am not able to speak at all! to top it all of there is a loud screaching sound constantly through out the dream.
When i snap out of it i am out off breath and sweating. This apparantly only lasts for a a few minutes but in the dream it feels like a few hours.
after looking this up on the internet i have found this.
http://en.wikipedia.org/wiki/Sleep_paralysis
Apparently 1 in 6 people suffer from this.