I have a 3.5 month old and I exclusively breastfeed. My breasts have regulated through the day, but since he sleeps longer through the night I wake up with engorgement every morning. So after his morning feed I pump for the same time everyday. I've been consistent with everything, but sometimes I pump out 5 oz, other times only 2 oz, why is that? This morning, I pumped only 2 oz, and my breast were still engorged afterwards.