Severe depression and/or burnout can have similar effects. I’ve been in a brain fog for years and it only started getting better with antidepressants. However, first you’ll need to make sure that there is no physical cause. Any good doctor will check your blood more in detail with those symptoms. There’s also the chance that there are several causes, not just one. You could have e.g. sleep apnea and also some other issue.

Are you taking any medicamentation? Even if it’s a common one like allergy meds, you could be one of the unlucky few with severe side effects.