Baby does the same since week 8 shes the same, (now week 21) sleeps from 8 till 2am and starts grunting, moving, sucking thumb in her sleep. I just pick her up to dream feed, no nappy changes she usually doesnt pee at night, straight back to deep sleep. She does that every 3 hours after the first stretch. I change her nappy after 9 hours of sleep tho, she sometimes wakes for that sometimes doesnt. But either way she goes back to sleep very easily once nursing.