I like to wake up earlier than everyone else, drink my coffee and do my early morning things, like reading, reflecting, planning my day.. just relaxing things. And finish with the hectic things as early as possible in the evening so that bedtime becomes soothing and relaxed, not rushed. Something that helped me early on with getting my home and life together was the FlyLady.. Google her! 😊
Establishing healthy boundaries. Your children obviously need care, but it's not helpful or healthy for them if you overwork yourself, as well as showing a bad example. Set a time in which you put yourself first each day: it's healthy for you and will show your children the importance if self care.
Time for yourself doesn't have to be hours long. It can be a few minutes here and there. I am not in that specific situation so it's hard to answer specifically.
I have no idea, but you have my deepest admiration and sympathy! I go outside to do chores or gardening, but I don't have near the intense load you do. Hang in and good luck!😉