I've had dreams within that i've been hallucinating and "woken up" within the dreams only to find that the hallucinations are still lurking. I dont think it means anything. I've had hallucinations in the past, my dream is constructed from past experiences all jumbled up and illogical. I've had dreams within dreams a lot when i get a conscious inkling that i'm asleep but my body isn't ready to wake up, so I just wake up into another dream. At least that's the way I understand it.