I do the stay-up-until-you-exhaust-yourself thing sometimes, too. Within a two-year period I lost my brother, my mom, and my house/car/a lot of my belongings (obviously the possessions were a much less meaningful loss, but it was still a shock). My brother and I used to work together and I had real trouble going back to that office, especially as it, too, was in sorry shape after Katrina. I finally had to quit for my sanity.
For a while the sleep thing was constant and I would go a full day or two, occasionally three, without sleep just so I could go out like a light as soon as my head hit the pillow. Otherwise I'd stay awake with my mind racing with unspeakable thoughts and worries. My dreams weren't so hot either.
Let me tell you from personal experience that sleeping pills do NOT work in the long term. You have to find ways of dealing with the underlying issues. Sometimes they seem insurmountable, but they aren't. Time does heal just about everything, and what it doesn't heal, you learn to live with just as someone who's lost limbs lives with accomplishing things in different ways.
Losing sleep will mess with your eating. It will mess with your weight loss. It will mess with your concentration, dangerously so if you're driving. Try to find ways to make your brain "turn off" that don't involve sleeping pills or staying up late; they're only stopgaps. What works for me is sleeping with lights on and a television chattering so I don't have silence in which to think too much. You might also have good success with thinking of good things--story or article ideas, paintings you want to paint, whatever moves you and makes you want to open your eyes each day.
I'm sorry you're having a rough time of it and I hope it gets better soon.
