Thanks @AlbertBridge, I'll make a start on it as you've written it. I really am overthinking it. It gets so jumbled in my head and I get so much anxiety over it, so it's really helpful for someone to just write it all out like that. I am going to have to call it the mo fo list, though!
If it's any consolation, I'm very similar to you. I can only give advice because it's not me! But it could so easily be me.
I ended up going freelance because I was always so nervous in a full time job. Always always felt I was about to be, or should be, fired. It was really stressful. I was only good at jobs where I spent most of the time interacting with customers face to face (like behind a bar, or in a shop).
My freelance career has been great - I'm a writer - because it's short term work, different projects, tight deadlines, and you get loads of feedback straight away.
I read that people with ADHD work best under pressure. We (I say we because I'm convinced I've got this) need urgency in order to focus. So, ambulance staff, A&E doctors, live-TV presenters... Those kind of jobs. Where you don't have the luxury of faffing.
When we don't have deadlines like that, we tend to create our own by simply leaving everything to the last minute.
ADHD people also often take criticism - or perceived criticism- to heart more than NT people. We're super sensitive, and highly tuned towards how people see us. Which might explain your anxiety now.
I bet you're actually doing really well at work. You might not be organised but I would bet money that you're creative, adaptable, engaging, fun, friendly and very bright. Please don't forget those qualities while you're beating yourself up for not having android-level organisation powers.
Massive hug.