Cavalier night terrors?

So recently my king charles cavalier has been acting weird. He would wake up from a deep sleep and start freaking out, tucking his tail, running across the room. Went to the vet at the middle of the night and they said he needed his anal glands cleaned out. Then about 8 hours later he did it again when he woke up from a nap. He was lethargic for about 2 days before, but he’s eating, drinking, peeing, and pooping normally. Could it be something else???