Preemie babies

Hi guys. Anyone babies were born a preemie always sleeping a lot during the day but wide awake during the night?  My preemie sleeps most during the day and awake at night. He cried when he wants to eat during the day but falls asleep during feedinng. How do you change that or do I just leave it the way it is?  Trying to put weight on him. He gained a few since he came home from NICU.  First baby in NiCU and born a preemie. I have two others kids but no problems, and were full terms.