There is a reason they say to let sleeping babies lay. By waking him up to feed you trained him to get up and feed at night, something my Ped said was no longer needed after the first few weeks. My son started sleeping through the night before 1 month old, and I was trying to wake him to feed, and the Doctor told M. to stop, and he has slept through the night ever since. Now that he has been trained to wake and eat at night, you have to re-train him to sleep at night instead. Start by trying to comfort him to sleep some of the time without food. It may be better to let dad do this if you are breast feeding so the breast will not be an option. Decide how many times each night you think he is really hungry, and how many times he just wants to eat or be held, and start from there. Both of my boys slept through the night by 3 months old because I never trained them to wake and eat, I just let them do what came naturally to them at night, which was sleep. Now, with your child being a preemie, it may need night nutrition longer than other babies, so talk to your doctor about if, and how often, night nutrition is really needed in your child's case.