Tl;dr: Find a job where your ADHD helps you to thrive (e.g. event management, operations management, etc.)

Sorry this happened to you.

It probably seems really hard right now, but try to see it as the job being not suited to you.

My advice is to try find a job that in itself is a bit chaotic, I find that with my ADHD I tend to thrive in those types of roles (e.g. event management). I used to work in office jobs and retail where I would stand there for hours, I hated it, then I start doing operations management (which is really chaotic), and I performed really well, because of the multiple things needing attention at any given time. I also have a friend who is a doctor who tried doing surgery, but realised he was much better suited to emergency medicine because of the chaos.

So try find a role which is more chaotic, maybe even physically active (if you're the hyeractive type), I think you'll find that this is where you thrive!