Hang in there bro at least you are on track to get it resolved. That must be terrifying. Don't feel to down for feeling that way at age 21.
I found out a year ago my best friend from High School whom I had lost touch with had to have a Kidney donated from a family friend. He was 21 years old. He woke up one morning and couldn't stand on his right leg it hurt so bad. Now he is married and quite happy.
Not bringing up the transplant to scare you just pointing out that it happens to people at all ages.