More seriously, ADHD, among others, is a working memory disorder. A way to cover this is to use "prosthetics" for it, such as a notepad that you always carry with you. If this affects you strongly, train your muscle memory to use it to note down what you were planning to do and to refer to it when you forgot.
In PC-speak, ADHDers have traded RAM for more CPU.
Thanks! I'm now working in a new role where there is no more ridiculous pressure or wild expectations and have been able to commit to working on a degree (because I fucked up the first one).
Work shouldn't leave you panicking on a monday morning or crying into your lunch.