The fact you lost the paperwork should be a pretty damn good indicator and this part made me laugh out loud. I'm glad to have been simply diagnosed by someone who just accepted my story as true. All this talk about diagnosis is just bizarre. It's not a 0-1 sort of thing, they have to trust you. Unfortunately you have to be confident and assertive because they will gas-light you in the name of being 'careful'.
Sports can be an important piece of the puzzle in the ADHD lifestyle. Especially high-intensity, game-like, engaging ones that you can identify with and be good at. I swear my executive self-control and discipline have improved since I started training tennis several years ago.