This has happened to me too, having 8 or so consecutive false awakenings (all of which were in nightmare format). That kind of thing really messes with your perception of what's real or not. Every time I got out of bed, I'd be attacked by something invisible on the other side of my door and "wake up" in bed again. When I did finally wake up, I didn't get out of bed or go back to sleep for quite a long time.