Can i get SSI if i already receiving child disability benefits?

Hi everyone, I'm 30 years old this year. I have had Lupus when I was 9. I've been in and out of hopsital throughout my whole life. I been near death experience like 3 times. I started receiving adult child benefits in 04 when my kidney failed. My dad is receiving SSD also and I get half of what he gets which is $581. I live with parents, i don't work. I use my money pay back my student loans, help pay the phone and trash bill for parent since i live there, and cc bills. That is where all my money goes. I was wondering if I can get SSI? Do i need to apply for this or get my file reevaluated? I do not have any assets myself. (no car, house, etc..). I think my medicare is almost going be obver because i believe after 36 mths after a kidney transplant it stops. so if you get ssi you will get medicaid. I don't know how i will be able pay for my immunopressent and dr bills. I have a lot of other problems but i don't want go into details. Any help i would gladly appreciate it. I'm from Tx.