Debilitating brain fog, tired sometimes with vertigo had blood, mri tests, all were normal doctors can't find cause please help! what could cause this?

There is a long list: The possibilities are several & cross into multiple disciplines.Thus ideally, you will find one doctor (perhaps an Internal Medicine) who can help you work thru specialty referrals & all the tests.Viruses,fibromyalgia,Attention deficit,benign positional vertigo,migraines, Lyme & chronic fatigue syndrome are just a few that often have normal tests.While they search I would trial some cmm approaches