The only obvious symptoms mentioned were “poor focus and concentration.” AHDH is often comorbid with other ailments, and from what you write sounds like something else might be at play.
Only a qualified medic can diagnose and they’d need way more than the info you’ve dropped on here. I’d suggest going that rout – we’re not qualified or insured to diagnose. btw people with ADHD often have strong problems solving and higher IQ levels, so not sure what the “fogging” is. Once I got organised and learn’t to focus I excelled academically. I hope that helps.