I have ADD and in a relationship where he has his children on weekends.?

Can anyone help me when the 5 yr old girl and 3 yr old boy are naughty....hubby says im too much like a nazi. We are great without the kids. But we fight all the time when they are there. I need advice. Can anyone help that has a similar situation or something? I hate having ADD sooo much. Im on medication and it does help, but need someone to tell me what to do???