It is going to take a bit of time to process this new diagnosis and how your life was so terribly affected by the failure to diagnose correctly combined with being medicated incorrectly. It is a horrible thing to go through but you can survive this grief.
I am 60 years old and was just diagnosed a year ago. My life has been ruined by the incompetence of trusted professionals who should have known better.
I have learned as much as I can about ADHD, allowed myself to rage and despair over the what ifs. Now, I feel better than I ever have. I am struggling still to rebuild my life but I have some hope. Believe me. You have plenty of time to build yourself a wonderful new life.
All the best,