Try melatonin. I find when I have to revert from night shift to day shift, the first night I need to be in bed early I always have trouble since I'm just not tired enough to sleep and I'll be lying there hours straight just trying so hard to sleep, hate that. Melatonin does tend to help I find. When I can't sleep I give myself a time, like say, 4am, and if I'm still awake by then I just get up and shower and stay up the rest of the night. If I fall asleep only to have to get up early it's usually worse than just not sleeping at all.