It takes time, you know? You just found out. Learn as much about ADHD as you can. I found that the more I learned, the less inclined I was to be overly self-critical. I’ve gotten better at recognizing what I can control and what I can’t. One thing that helped me was to watch for triggers – what kinds of situations set me off? If can avoid or minimize those situations, I’m going to feel – and act – a lot better. When they say “tailor the environment to you” that’s what they mean – put yourself in an environment where you can be more successful. If I can’t control my responses, I don’t go into situations that work against me. It isn’t worth trying to be a contortionist to make myself do things I’m not wired for. (And by the way, I’m a terrible driver and only drive if I absolutely have to, LOL.)
And I agree with Jim C., it’s important to be with someone who “gets” you. My husband is a mellow guy with a sense of humor. If I start flying off and losing it, he’ll usually tease me about it and make me laugh, and that calms me down. It helps a lot to be with a person who will say things like, “You’re in orbit, aren’t you? Do I have to send the space shuttle up to retrieve you?” 
He’s learned not to take my tirades personally – I don’t like that aspect of myself, I can get pretty psycho sometimes, and need to get better at recognizing when I’m starting to go off the deep end and just take a walk or something – but I sure do appreciate his ability to let it roll off of him.