I've been having an experience very similar to deja vu, but not quite the same. I've developed some kind of accidental mental hack where reading nursery rhymes

I've been having an experience very similar to deja vu, but not quite the same. I've developed some kind of accidental mental hack where reading nursery rhymes to my kids makes me fall asleep. I could be wide awake but I'll literally open page one of a book and yawn immediately. My wife thinks this is hilarious. As I'm just reaching the edge of losing consciousness, my brain starts to manufacture false memories about whatever nursery rhyme I'm reading. For example if I'm reading "sing a song of sixpence" my brain will say "ah yes, I remember this one, the king and the maid are having an affair, and the queen learns about it and has her killed". Then I'll shake off sleep and realise that it was a false memory It's an odd feeling. Similarly, sometimes when drifting off I'll find myself at the end of a train of thought which I did not have. I don't know how else to describe it. It's like my subconscious was having a train of thought and i jumped in and claimed it.