Night shifts suck big time. I work 12 hour shifts from 7 to 7 and I find that I have the most energy if I come home in the morning and sleep to 11:30 0r 12:00 get up, eat, and go to the gym. You will find that your
energy levels will be lower but that's night shifts for you. I usually try to sleep for a couple of hours before my night shifts it seems to help me stay awake during the night and I feel better the next day. I always eat twice during my nights as well once around 2 or 3 and once before my shift is over.