Here Are My Symptoms, Ataxia, Failed Romberg Test, My Memory

here are my symptoms, ataxia, failed Romberg test, my memory is terrible, I have a hard time finishing my sentences because I cant find the word in my head. I will have vertigo, but it runs in blocks of time. Example I haven't had one in 5 months, but once they start will have a couple every week.
This has been going on for 2 yrs. I see a neurologist who ordered an MRI of the brain but it came out fine. What is wrong with me?