Struggling with work and fitting in / not feeling like I'm failing

Hi,

I work in the aged care industry as a care partner. I have been off for approx. 1 month over the last quarter either because of physically illness or mental health. In that time I lost oversight of a budget for two client who not have to pay out of pocket 3k. I can't deal with the guilt the anxiety the distress. I feel like I fucked it up. I don't know what happened. I don't know how to tell them. Why I couldn't manage when everyone else in my work place always is on top of things or meeting their billable hours, where I seem to struggle or just drift from one half finished task to another. I keep being asked to help rostering, I say yes because they beg then get told to let them know when I'm struggling / need help. But then when I do I get asked again to help or to sign up a new client. I can't do this. I'm failing and it's not helping me or my mental health and I don't know where to start or to even do anything. I've also been seeing some autism and ADHD content and ngl I can relate a little so I'm also very aware I may have a bit more then depression. I know I have a slight intellectual delay from a genetic test. I hate that people seem to think I can do well but I can never seem to deliver or actually do well and succeed. I was fired a year ago after extensive bullying as well. Ngl I let them fire me for the plot / money and to not let them win by quitting.

I just idk what to do with work or employment or how to even find an industry or role or manage this one or just exist as a 39year old who works.