Supposing you got struck by lightning in your sleep. would it wake you up?

Only if it did not: Kill you. If you were struck by lightning in your sleep, the lightning would leave very bad burn wounds. If the lightning happened to hit your head or hit your heart then there's certainly a possibility that you could die from that. I would expect that death to be immediate and not awaken the person involved. In my residency i saw a man who was hit by lightning on three different occasions. He had three very jagged long and fairly wide burn scars from these three different events.He remembered them very well and was obviously very much alive. Best wishes.