I don't have children,so I'm as much use as a chocolate teapot (which I could eat in one go, by the way),but what I think I would try to do is remember that a major part of doing this crazy diet is to benefit your children, so that you can have nearly as much energy as them.Like I say, I've never faced the stresses of having children, so I'm sorry if I'm talking tosh.
Best of luck
Penny