Why are you doing everything?
Simply not fair.
Have a hard look at the list of jobs that you do.
Stop doing laundry for those that don't appreciate you.
Stop cooking every night.
Decide to cook 3 nights a week and tell them to fend for themselves with toasties, soup etc.
Stop doing any taxiing for ungrateful child.
Dramatically reduce your cleaning by simply leaving things.
Stop giving ANY money to lazy children who won't treat you with respect and help out.
Look at moving into another bedroom to give you space.
Stop buying ANYTHING when shopping that others like.
Cut your shopping back to the essentials only, to cover the bare necessities.
Stop being a doormat to your family.
They will treat you as poorly as you allow.
Can you go away for a few days?
Even go and stay in your parents house if that would give you a break.
Can you change jobs?
Who benefits from you being paid badly?
Where is all the money going?
Can you look for a better paid job?
Hang in there, but see how you can help yourself.