Don't eat during the night. Try to keep to meals during day, maybe having one early on into shift.
Getting sleep is vital, invest in complete blackout curtains, get earplugs and a sleep mask, turn off phones, unplug landlines and make sure you tell people not to disturb you.
On your days off get out in the fresh air, try to get a day shift job as soon as you can, night shift is not good for anybody.