Sounds like your sleep cycle is off. Babs, as usual, gives you some good hints. Ryano's post is helpful too. I would look at what you are doing to "Wind down." If I were working 3-12, I would be looking to get myself in bed by 1. No TV, absolutely no video games or computer, they can over stimulate you quickly, dark room. Make sure you have your heavy meal during your break at work, take something with you to eat on way home and focus on heading to bed. Cut all caffeine by 9PM. Set a wake up time, 9 or 10 to make sure you get adequate sleep and then get up at the same time each day. That should leave time to get a workout in, run a few errands and be to work on time.
My experience, most sleep issues are lifestyle issues. For younger folks it tends to be over stimulation via diet or video products.
Just my 2 cents.