C.S.
I was in this same situation years ago.
If you haven't done it already, I would ask your husband to please go get a job, any job, to bring in more money. I would also ask him to take over managing all the household finances, like balance the check book, pay all the bills, budget how much you and he will spend on food, kid's stuff, utilities, etc. You just turn your check over to him and he figures it all out from there. That will give him a very clear picture of why one income isn't enough and should motivate him to do something about it.
If you are concerned he will just spend all your pay check on bad choices, then I would suggest counseling. Your other three children will eventually grow up, but he may not if you make it too easy for him not to.
As the only woman and only breadwinner in a house full of men, you have a right to expect more. Someone who loves you should not want you to be under this much stress.
Good luck!