You do need legal advice, the law center suggestion is a good one.
And, legal aide. Also, you usually can have a meeting initially with a lawyer gratis. At least it would be "practice" for being able to go that route. Online research can help too--you will find a lot of info on what is avail. where you are, state laws etc.
I am going to suggest you speak with a manager at the bank where the joint account is held and ask them to explain their policies re: joint accounts. It might help you to hear someone there tell you that he cannot just take you off as he has threatened (as healing4me has posted.)
If you can put all your change somewhere---it adds up---when my kids were young, they opened bank accounts with the pennies we'd tossed in a bag for years---ended up being over $400.00 in pennies alone. And, a job yes---don't be afraid to apply for any entry level job---full or part time, whatever you get is yours and that is so important.
What about sitting for other's kids in their home? There is often a demand for that, and you would be out of the house and making some money---that is if it something you feel you could manage. If you drive, there are always early morning paper delivery routes, that don't pay well but again, it is something----(keep your eye on local want ads, something just right may turn up) Do you live in a rural/suburban/or urban area? What is around you? {& please don't dismiss the women's shelter option, they may also be able to help you hook up with services and legal advice} Be safe, keep hope and gather strength. We are all here for you.