Hi, spaceboy, sorry you are in this predicament.
You pretty much have to have a documented background of not being able to work for a diagnosed illness. In other words, you have to have a medical doctor that finally pretty much says, "Hey, you shouldn't still be working" and/or a past with documented jobs where you were dismissed because you could not do the work.
Or, you grew up getting financial assistance for illness and have switched over from your care-taker/parents getting it to you getting it yourself.
As far as straight financial assistance, not certifiably disabled or anything, check with your city, county, state, and private non-profit agencies:
Missouri Department of Social Services Home | Your Potential. Our Support to see what you might qualify for.
Were I you, I would see if I could figure something out with your father, taking some courses to train in something you might find less stressful or some way to use your driving services, etc. I would find a local low income clinic and get a physical, see if you could start addressing your physical difficulties in a straightforward, documented way to see what you've "got" and get an idea of where you might go from here. Your county community college might have vocational testing services that could help (age doesn't matter anymore, people of all ages are going back to school now) or maybe you could do something like start your own janitorial services company and hire part-time workers, etc.
I would get my health totally checked out at a local non-profit clinic if I could and I would talk to my father, see what he was willing to provide that I could rely on (like room and board so you don't have to worry about that and can concentrate on other things) and go to a local college to see what they may have to offer for skills testing and retraining and ideas for alternate jobs I might like to do/be qualified for as well as the State agency
JobsMoGov - New Premiere Employment Resource for Missouri - for Job Seekers