Laleh, so sorry to hear you're going through this rough patch. Unfortunately, these symptoms can happen even after 3 years have passed, let alone 2 years. But the fact that your tumor has shrunk slightly is a good sign. At least you don't have to worry that your symptoms are caused by a failed treatment.
An AN needn't swell in size in order for there to be inflammation present. If I remember correctly, Dr. Chang called this phenomenon "clinical inflammation." In any case, it's clear that your balance nerve is irritated for some reason, possibly from clinical (internal) inflammation. Try cutting out foods that cause inflammation (such as refined sugar) and see if your symptoms abate. Also try taking some anti-inflammatory drugs (ibuprofen or Aleve) or natural anti-inflammatory enzymes (bromelain, Flavenzym or Wobenzym) and see if that helps. (Take the enzymes on an empty stomach, or they won't work; take the drugs on a full stomach, of course, or they might cause your stomach to get upset.) I bet it does help, if only providing partial relief.
Also try to walk a lot. That will retrain your brain to ignore all the imbalance and vertigo signals it's receiving. Of course, have someone walk with you to make sure you're safe and can make it back home!
The more you can cut out foods that cause inflammation and exercise your vestibular system, the sooner you're likely to feel better.
Just my two cents...
I hope it helps!
Best wishes,
TW