Well, I was going to suggest taking a shot of NyQuil. . . I know I joke around about it lot, but seriously it's the one thing that will always put me out no matter how keyed up I am over things. .
But since you are there alone with your son I'd guess you wouldn't want to be that zonked in case he needed you. . . it's never really done much for me, but I know other people (in addition to those on this thread who mentioned it) that swear by melotonin, so I think it'd be worth a try.
I'm sorry you're dealing with such a painful situation Denise- I've been there and know how awful it is. . .
I think Michelle's advice is good and even necessary to help even begin to come to terms with what your facing, and if things drag on and you feel like you need it, don't hesitate to go see a doctor and let them prescribe something to temporarily help get you through this, be it an anti-depressant or sleeping aid or whatever they think will work best.. .
There are some things in life you just have to endure and do what you can to just get through them. . although it may not feel like it now, you will get through this and the pain will eventually go away. . . I know that's not comfort now though - so here's a {{{hug}}} and I hope you find something that will help you sleep at least. .