apinecone

Well, I guess I sorry but happy at the same time about your ADD Dx: to paraphrase you "it's about time!" But you have alot of that (lifetime speaking) and now you know and (1) can compensate for it and (2) won't have to spend your whole adult life or any major part of it 'not knowing'. Often, way adult-ADD Dx'd people, like me, think: "what could my life been like if I'd have known sooner!!" Presumably "better", but that's up to you to a certain extent, so to that extent: listen up and pay attention, dude!! [couldn't help myself; sorry]
Pay attention to how this 'new' thing in your head 'works' [it's not new but you are new to how it works, so understanding how it works and how it works in you, I think is a main key to 'what should I do'. If you haven't read some expert material, that's a good place to begin. I recommend "Driven to Distraction" by Dr. Hallowell, who is an MD with ADD himself, which helps ALOT, I think.
As for self-esteem, here's some points that might help your perspective: (1) you can't change the past, but you CAN learn from it, so do that to the best extent that you can; (2) there is nothing "wrong" with ADD per se; if you feel it's a 'stigma', YOU are wrong-- stigma is in the eye of the beholder, so if that's a problem, try educating THEM; (3) be aware that this stigmatic effect can put you at an unfair disadvantage, so learn more about your 'rights' and how to better handle 'public' awareness about your condition; (4) learn how to take advantage of the advantages that having ADD itself might give you and also how to prevent or reduce the negative effects (like being forgetful/late, over-concentrating on things, etc.)-- these will help over time in both more win-win and less lose-lose ways.
And network-on-your-support-system; misery loves company, so you don't feel like the lone ranger all the time, right?