Yes, you are over reacting. BUT its understandable.
BTW, Albert Einstein was asked by a reporter, how it felt to have to work with people that weren't as smart as he was. He replied, "All of us are ignorant, just in different subjects." I did something yesterday Einstein never learned to do, I tied my own shoes.
People who are compassionate wish they could help "make things better". They say things that to them are trying to help you, but sometimes don't because your perspectives are different.
Just remember, doctors "practice medicine". Its not an exact science. I wish you well and hope the diagnosis is wrong or that your son gets better. I was a substitute teacher and often helped in classes where autistic kids were present. I feel for you.
Good luck to you and yours.