How do I stop having meltdowns?????

Im a young woman and today I figured out that I am having meltdowns. I have had it my whole life. When I was 15 I got diagnosed with autism and ADD. I have never really figured out how the autism is seen in me and never my self think about having autism. These “meltdowns” I have been having since I was little was just regular and something my parents thought would go away and I thought the same. In the same time I got diagnosed I also got a boyfriend that I have been with for 2,5 years now. In the beginning everything was fine. But when we started to get to know each other better and started being together most of the time we also started to argue more. And I started having meltdowns and panic attacks. My boyfriend has adhd which I don’t know is worth mentioning. But I’m pretty sure he reactes ”wrong” but it is not he’s fault because he doesn’t know what all of this is. But he says more stuff I do wrong so I become more and more panicked. And when I starts to chill he says stuff about how I ruin everything doing it likes this. What I wanna ask is how do I handled situations by my self, how do I stop having them, because it affects my relationship so bad and I seriously don’t wanna louse this guy I’m am not joking. Please help meee.