I cannot afford to run the house, pay all the bills, a car (needed for work) and feed and care for three adults, three cats and 6 chickens!
I don't know many people who could.
Your DH shouldn't possibly continue to contribute to the financial wellbeing of an ex-wife (or soon to be, re: the divorce issue) or 3 grown adult children.
You shouldn't be expected to either. It's not literally possible in your case, but neither is it desirable.
Your son is a seperate issue to the money side of things, but perhaps the silver lining of your reduced financial state can help - if he's never moved out of home and expects to be fully funded at home, there's clearly a life lesson you've failed to teach him, both, as parents (or maybe you've tried and it's just not sunk in).
Basically, you need to start making pro-active steps to getting your financial affairs/stability in order. If you can't find fulltime work but can't afford your bills, ensure you're getting any benefits you're entitled to, and seriously consider downsizing, renting rooms, doing odd jobs, setting up another business on the side (you have access to the internet) - anything really, which is what everyone has to do to make ends meet. You've just been shielded to this fact before now if you've only ever had to work 26hrs a week and expect an ex to continue to fund an unsustainable lifestyle.
The best of luck to you.