Re: undiagnosed vertigo
The reason I focused on the prevalence of migraines is because Migraine Associated Vertigo is found in many migraine sufferers. It seems that your dizziness does correlate with your migraines, there seems to be a pattern. Additionally, your sensitivity to light and sound support the possibility of MAV.
I would discuss the possibility of MAV with your doctor and get a referral to a neurologist if necessary. There are special medications which have been quite successful in treating MAV.