Welcome JustaMom!
The decision to medicate was not made lightly in your situation. In fact you son seems to be the first to recognize what might be going on. That to me shows that he has had the desire to preform better than his grades were showing. In my limited experience that is not typical of the Classic underachiever.
If your son finds that the medications help him (as they apparently do) then you are doing what is in the best interest of your child. I agree with the other posts to use the critism as positive teaching opportunities when possible and let it roll off your back when you can't.
Gifted children with ADD/ADHD can present very differently from a ND child with ADD/ADHD. I am impressed that given all the adversity that your son and your family have gone through that he has stepped up and is doing so wonderfully now! All of you deserve to congratulate each other and continue to build on the positive effects you are experiencing
