Another interesting thing, somewhat related to this sleep paralysis, is to dream youre dreaming. Sometimes i am dreaming, then i "awake". Or rather, i think i have awoken, cause the dream i was is suddenly interrupted, but im still dreaming. Then, i "awake" again, but still am dreaming... Sometimes it happens a lot of times. Once, i feel i had "awakened" almost 10 times. And still was dreaming!! I was becoming scared, cause i was very conscious i was dreaming, and though i tried to awake, i only could dream i had awoke, and not awake in the "real world". Then, after some minutes of struggle, i managed to really awake...
It happened after a night of heavy smoking, and i was beggining to smoke in that times. Dont know if there is a relation... it had happened before i started to smoke, but not with so much dreams inside dreams.