Bedtime Stories

I don't know if this is a common experience, but it happens to me all the time-- when I'm reading in bed, at night, and I start to fall asleep, I'll nod off for a moment or two, but I'll dream that I'm still reading-- and my brain will invent the text-- so I'll still be reading along, but not really, my eyes are actually closed and my mind is making up what comes next in the book-- and then I'll start and wake up and I'll reread whatever I was reading and it will be totally different than what I just "read" in my previous half-conscious state . . . I'm assuming this happens to everyone who reads before bed?