This:
there's nothing worth going to war over more than the safety and well-being of your children.
My word of advice (and I do feel like this is one place where I can give some without violating forum rules) is: Take. Good. Care. Of. Yourself.
Make sure you get enough sleep. Make sure you eat even if you only have to view it as refueling (if you don't feel like eating). Make sure you go out and get fresh air. A walk. Breathe deeply. Listen to music that lifts your spirits.
I'm saying this because custody fights can be marathons. And you have to pace yourself. But you can do it. You absolutely can. Lawyer on your side, truth on your side, you've got nothing to fear.