Hi Barnside
I can only say that if yu are worried about getting a correct diagnosis you should see a neuro-tologist. That is to say a neurologist who has specialist training in balance disorders. You may find that some vestibular rehab exercises help speed your recovery. I think that the US has many more specialist balance centres than the UK.
It does go away - It can just take quite a while to subside. I met somebody last week who got this just after completing his IR. He is flying for a living now back to normal, but it did take him nearly a year to recover.