I'm so sorry you're going through this right now. I, too, struggle with self-harm and suicidal thoughts, although mine are not caused by stress in my life. If you want to talk, I'd be happy to listen (or read, I suppose) and I hope things get better soon.
Oh, and about the stomach and headaches, I had a friend who did this and it turned out they were just a physical manifestation of her stress. I don't know if that applies to you, but maybe.
Even more, about the self-harm and suicide, it's probably best to talk to someone about that, or at least check out the self injury and depression forums here. It's never normal to seriously think about those things and both lead down a slippery slope.