My husband suffers from this issue as he works nights as well. I have learned that when you set yourself on a set schedule, your body handles lack of sleep much better. When you are on a rollar coaster sleep schedule, your body doesn't function well and even the sleep you do get doesn't seem enough.
Weekends (or whatever your days off are) are more difficult as you want to be social during those times like most of the rest of the world, but by Sunday, your exhausted and haven't slept all day to prepare to go back to work because you slept all night Saturday night. It really seems like a vicious cycle but like I said, figure out a good sleep schedule and you will get the best and most fulfiling sleep.