There is nothing wrong with your feelings. Feelings are never wrong, they just ARE. Take a few days to process them, but don't act on them until you give it a couple of days.
Try focusing on you and the kids. What is lacking in your life right now? Can you fill that need with something else, something healthy?
I know it hurts. I think we ALL do b/c we've been through it. The best advice I got when I was in the worst of it was that it DOES get better (it does) and that I only had to make it through one day at a time. So, have faith that it will get better no matter what and focus only on the present - not the past or the future.
And post here often. Vent, complain, whatever. It helps getting it out and just knowing there are others out there (who you don't even know) who have been through it and know what you are feeling. You aren't alone.