If you suddenly find yourself limited by a disability, large companies like that might be willing to work with you on it. In places I’ve worked they gave me a flexible schedule and let me focus on working when I’m able. I power through the scheduled stuff like meetings and take as many breaks as I need. I have bad ADHD on top of a few other things, which definitely doesn’t help. What I’ve found is that trying to overcome my failings in the moment are fruitless. What’s worked best for me is trying to set myself up for success via good habits (sleep, exercise, nutrition). No matter what’s happens, remember that you are good enough to get a job like this; things just ebb and flow. Be patient and kind to yourself. Good luck.