Should I apply for adult disability or stay on adult child benefits?

I had lupus when I was young. I am now 30. I been in and out of hospital many times and has cause me many problems. It kept me from finishing college or work. I am receiving adult child benefit under my dad. About 581. I live with my parents. I have no ets (car, house,etc) I had transplant in 08 and this nov. my Medicare will be over since it almost 36 mth after transplant. I was wondering with regular SSD if I can get continous Medicare. I don't know how I will pay to go dr. And my immunopressent. any info I would greatly appreciate it.