Parent guilt. We all have it. Kids will experience dysfunction throughout their lifetime. Let your anger at yourself propel you into action to change the situation. You will feel better, and inevitably so will your kids.
I had a physical last week and shared my situation with my nurse. She laughed when I expressed guilt, and said "well now they will have something to talk about in therapy!" I have to admit - it was funny thinking about it that way. I mean, my parents weren't perfect, there's weren't either. We are all imperfect people doing the best we can with what we've got.
You've done the best you could have given the situation you were in. Believe in that.