It will be OK. I too felt like you, everything down to contemplating suicide. Yesterday, 2 weeks into the seperation, I told my sister that it was as bad as I imagined it would be. It still sucks, but it really isn't as bad as I imagined it.
I have 2 pieces of advice: 1. Enjoy the kids when you have them. 2. Enjoy GAL'ing when you don't.
And if you get real lucky, you can do 1 & 2 at the same time