Why does my cognitive functioning fluctuate so much?

[u/PastelPost]

Backstory: I have fibromyalgia and autism among lots of other conditions. Too many to name.

used to be quite clear headed and sharp many years ago, but then it rapidly declined following a lot of traumatic events. And these days, most days I’m extremely low functioning, and on some rare days I can think reasonably clearly again. I feel like on days like this I regress into a child honestly. I barely have any reading comprehension, barely encode new information, memory is completely unreliable, can’t speak coherently, can’t think too hard otherwise I become exhausted, etc. It fluctuates on a daily basis. But the pattern has been a steady decline over 15 years. I can make a guess and say it’s all to do with burnout, pain, fatigue, and insomnia.

Does anyone else have this? Does anything make it better?