this has happened about three times over the past 3 months, as ive been dropping into a sleep suddenly my head feels as if its closing in and i hear what i can only describe as 'white noise' i know the noise was in my head and i know the house was silent, i also suddenly realise that i cannot move my head and i cannot move my arms or anything in fact, i try really hard to move my arms but i cant, i dont feel any physical pain or numbness i just literally cannot move, this goes on for the longest two minutes (i think) im scared the whole time and then when i can finally move im out of breath,, please please if anyone knows what this could be, tell me im scared to go to sleep!