Is there a program to help pay for doctor visits, prescription medications, and other medical bills?

I have started having some serious medical problems over the last year and I need to be examined. I have no way to pay for anything. I cannot find a job but even if I do I still won't be able to pay for all the tests and medications I may need. My parents are supporting me but they can't afford to help me with this. I have no insurance and I am not eligible to get on their insurance. I am only 20 and I have been having symptoms ociated with diabetes, hypothyroidism, depression, acid reflux, and too many others to list. I also was in a car accident (mechanical defect) where I had a seemingly minor head injury but I have been started having headaches and pain in my eyes and other problems that I believe may be from the accident. I don't know what to do. I am so scared that there may be something seriously wrong with my head. Does anyone know where I can get help?