I Can't stop being nasty

I have been married for 3 months, before we were married my wife and I were together for 4 years, The problem is that i can't stop being nasty to her and i feel ashamed and disgusted at myself for the things i say to her, I love her so much and don't know why i do it but if i have a bad day or something i just take it out on her and when we argue (usualy she starts an argument over something i haven't done) it always escalates into a huge fight and i say some aweful things, then afterwards i regret it and think there was no need for any of it to have happened. I am almost certain i have ADHD i have all the symptoms i have read about to a pretty extreme degree so its either that or i the biggest asshole in the world and have been since i was about 13, I am going to the doctor on thursday to try to get treatment but i'm worried they will not take it seriously and fob me off. I don't know what to do all i want is to be a normal couple and i am destorying our future together i feel at the moment that i should end things for her sake because she doesn't deserve to be treated like this.