You need to take time away. You need to put yourself at the top of the priorities list, and stop thinking of that as an optional choice. Really, honestly, this is at crisis point now.
I guess the only time this is going to be possible is in the evening? So you will to just get up and go, every evening, as soon as the children are in bed. Unless your husband works evenings? Sorry, I can’t remember what shift pattern you mentioned.
Go for a walk. It isn’t much, but it’s fresh air, and most importantly it is time away, in silence, alone.
It will help. It won’t fix the shitload of problems you’re facing, but it will be the first step to getting back some time for yourself.
Then, on the weekend out of four that your husband is home, you will take yourself away. If he kicks up a fuss you need to tell him to fuck off and do it anyway. If you have to get up two hours before everyone else so that he doesn’t have a chance to moan and whinge at you like a man baby, then do it.
You will take the first three hours of that day, 9-12 - no negotiation on that! - And you will go to the library, pick up a book (or buy one if that’s more convenient), get yourself to a coffee shop and have breakfast, a couple of brews, and you will sit and read and have time to just be.
It’s not a lot. It won’t fix the shitload of problems you’re facing, but it’s a start. You need to find the person you were before life beat you down so badly. And you do that by starting to awaken that person.
You cannot afford not to do this.