I agree with one of your statements: the medical info is useful, but certainly not critical. Family does not equal blood. Your family are the people who love you and care about you. That is your REAL family. Does it really matter who you look like? And why would being adopted cause anxiety? Sure, there may be a genetic component to anxiety, but for all you know, no one suffered from anxiety.
I am not adopted, but I think you do your adoptive parents a big disservice not thinking they are your real family. They, for whatever reason, chose to adopt a child who needed to be loved. What if you had of grown up in foster care, going from foster home to foster home, never knowing the love and support of "parents" who love you?
Is this rant because you're angry at your parents for forcing you to prove you've driven beyond your comfort zone? Maybe they just want to help you realize you CAN drive outside your comfort zone, without anything terrible happening. Try to put yourself in their shoes....