I'd first off get started by just asking (be very forward) for a referral to a Neurologist for a proper exam. Furthermore, I know this sounds weird but in some places you may find an Optometrist (yes, not an Opthamologist) who specializes in patients with neurological conditions, vestibular problems, etc. They aren't easy to find, but they really do exist (I have one of the best).

You shouldn't have to settle with the lack of investigation you've been given regarding your health and your quality of life. It has a lot of potential to grow into larger problems if it continues untreated. While many assume lack of sleep typically results in fatigue, it can bring a lot more problems than just that.

I normally have similar symptoms before or after a seizure. What I can suggest to help out (comfort wise) is to sleep with a television on. I keep mine on to add some light and to drown out the buzzing sound. If I had a large seizure, the sound is so bad I have no choice but to deal with it until it leaves (so loud I can't hear anything else).

Another thing you should do if you haven't yet, is get your blood pressure tested. The problem with vision and hearing disturbance is they happen to be a symptom for a lot of things and sometimes they come alone and unexplained. Regardless, you should keep moving forward until you are happy with your treatment.