I am so terrified of being like my parents that I cannot stop crying if I yell or get angry at my kid

I truly don't know how to deal with this and it's extremely stressful for my. Both my son and I have been diagnosed with ADHD. He struggles a lot with impulsivity and can be violent sometimes (hitting/kicking, he is only 4), which triggers my anger quite a bit. I don't want to yell, but it often is the only way I can get him to stop doing something. Usually by the time I'm yelling, I am completely freaking out internally, and almost always burst into tears after I'm done yelling and will start apologizing profusely and saying "I dont want to be a bad mom, I'm trying my best", etc., while crying. It is nearly impossible for me to calm down in a timely manner afterwards. I just feel like a despicable person who deserves nothing and is mean to a kid who can't control his impulses. It just feels so deeply, morally wrong and I just can't forgive myself. My kid is a sweetie and I don't want to be putting this on him, but I don't know how to stop these emotions.

I was yelled at a lot by my parents my entire life (even into adulthood), and often over things that are opinion-based. As little as five years ago I was told "I know nothing" and wasn't smart enough to make decisions, etc. My mom has always been extremely critical of me about everything, from how I dress, how I think, who I am friends with, everything -- even shit like not having perky boobs now that I'm nearing middle age has to be pointed out to me. I'm an only child so I never had any real witnesses to this behavior or anyone to be on my side. No was never taken for an answer, and basically I had to flip out on my parents to get them to stop or to listen to what I was saying, and I would feel tremendous guilt and desperately want to be "punished" so I could "do my time" and be absolved of the guilt. Instead, I just knew I had hurt my parents and would be given the silent treatment or treated passive-aggressively until my mom decided she was over it.

I am so terrified I am screwing up my kid even more than my parents screwed me up, because he sees me cry so much. I had extreme social anxiety as a kid (I personally believe I'm on the autism spectrum but have not been diagnosed), and would frequently cry at school or if I was called up to the front of the class. I have multiple memories of just standing up in front of a group of people and being humiliated, either crying or on the verge of tears, and no one helping me. I have never been able to control my tears. I just feel like the worst mom ever and so alone. Any other parents feel like this ever? I just cannot believe I am a yeller like my parents, even though I do so many GOOD things that they didn't. I just want to know what to do and that I'm not alone and I'm not just ruining my child. I love him more than anything and I don't want him to hate himself the way I have always hated myself.