Welcome, IT. I hear you!
I agree with-the others, that you've got to break the vicious cycle, which you can do with-the help of a family therapist and the right medications, as well as new parenting methods.
One thing I would suggest is not to try to change everything at once. Pick just one thing for a week or 10 days (or even a month, depending upon your kids' ability to absorb change) and just work on that. For example, if it's being late for school. Or if it's yelling at you.
Then have one consequence, which is not yelling 
and follow through. For example, maybe one of the kids has to walk to school. Or they go in on time, but are wearing no shoes and socks (you'll have to drop off the shoes later but maybe the embarassment in front of other kids will be enough, Know what I mean??) No arguing, no I told you so, nada. Just like it's normal.
Then after a few days/weeks, move onto another behavior.
Welcome. Here's a warm bath for you:
