what is wrong with me and i dying in my sleep?

I wake up gasping for air and i feel my mind and body is dying. sometimes i am not even completely asleep when i feel the attack coming on i get up quickly to call for help. it can last from 1min. to 3 minuets and after i feel week and nausea almost drained. i even thought it was an epileptic attack but i was sent to a sleep study and came out fine. sometimes before an attack i get so sleepy i cant keep my eyes open and by body feels strange and i know its coming. it happens around twice a month. i have even woken up with one and my body is shaking and i feel as if my brain has gone dead. i got one so bad once that when i got out of bed by right leg was completely paralyzed and i fell to the floor. i was taken to the hospital and they took all kinds of tests and nothing came up. has anyone else felt like this?