Yep, I agree with James and Helen, find another specialist asap. The diagnosis “anxiety” is not going to help you find the right medication to treat migraine associated vertigo. It will delay your recovery.
Certain specialists diagnose mental health issues out of ignorance about migraine. The fact that your neurologist had never heard of MDDS is alarming.
Migraine is a physical illness with physical triggers – some of those triggers can be mental health related, such as stress, but there are many other kinds of triggers (hormonal, dietary, weather, smells etc.) and the vertigo is the result of a physiological problem.
And yes, anxiety is often a result of MAV. Being dizzy is scary and it takes a lot of time getting used to. But anxiety is a product of MAV, not the cause.