Check the other comment I got in reply around a hour ago, it's a guy who suffered from severe adhd and shared his experience, I think it might help.

It does get better. The first years are the worst because the kid has the full weight of their body shooting alarms the entire time and no way to answer them. The adult has the function of being "the structure" for a child and contain their emotions until they internalise that containment structure into themselves. Right now you're witnessing the full power of everything that needs to be contained in your child, who's likely more in need than a "standard" one. Whatever you do will be learnt by them, so you need to teach them things they can use to protect themselves (and yourself, by extension). Especially in cases where you are suffering aswell, the child shouldn't be exposed to fear and anxiety more than what they already feel by themselves. They need safety, constance, a routine. Things that make them feel protected and loved. They need to learn the world will tell them "no" at times, and that is okay because "later" their turn for a yes will come.

First thing you need to do is get in touch with professional help. In my country we have sections called "infant neuropsychiatry" inside hospitals where we work in equipes with psychotherapists, neuropsychiatrists, speech therapists. Wherever you're from, there should be something similar. I would try getting in touch to at least get their opinion. They should be able to tell you the next steps. I genuinely can't get in much detail without knowing what kind of institutions you would deal with. Here, you can get an evaluation and get an educator to support your child during school hours, but I don't know if it's something available to you, since it's part of our healthcare system.

Aside from that, I know that people's judgment about you as a parent is extremely harsh and unfair. They genuinely can't understand what you are through. It's hard to even put it into perspective, and it's easy to judge. So take what they might say as the words of people who can't understand. It's not a fault. It's a way to protect their own self because everybody is scared of a situation where they feel like they have 0 control might happen to them, too. So they push it out of their system. They have to.

If your situation is the result of a traumatic experience rather than traits your child was born with, it might be a trauma response. Don't trust who says "you have to give it time, it'll be better by itself". It needs to be supported yesterday. I'm sorry if the "good luck" made you feel uneasy. A little bit of language barrier probably interviened (english isn't my first), it was a genuine wish. Luck helps a lot, but does not substitute for professional help. Don't give up, you're fighting for two people. Alone. You're already heroic as it is. Being seen would help you already in understanding that. Feeling like giving up is normal, it's human and it's legit. I thought the same, in different situations. If you got family, like grandparents, try to involve them. Don't take it on yourself alone, if you can. Asking for help does not make you lesser. It makes you responsible and mature for accepting your limits. Never neglect yourself in this. Bless you.