I have had a something similar in the past and since then too, on and off. I dont think it has been as severe as the original poster describes, but for me it was like a transient dizziness, sometimes accompanied by a feeling of fluid in the ear area on one side or both...hard to describe. Only lasts maybe 5-10 secs or so. Basically, I have found out that it is related to a very very minor hyponatremia that can occur when one drinks a lot of water, juice, soft drinks within a few days and coincidentally has a low salt diet during those few days. The very slight hyponatremia in my case can cause a slight disbalance in the ear fluids, leading to a transient dizziness. Obviously anytime there is dizziness one should get checked to r/o arrythmias and brain AVM's etc, but if the dizziness episode is not accompanied by palpitations but is accompanied by a subtle feeling of fullness in one or both ears or any kind of unusual feeling in the ears, chances are that it might just have to do with fluids and internal anatomy of the ear which has subtle variations in different people.
Visually assess your veins to get some idea of your body fluid status, being physiologically, but not necessarily pathophysiologically, hypervolemic might be a clue. Also, if ingesting a pinch of salt improves the situation, then it might be like what I have. Considering going to a neurologist or ENT as appropriate. Oh, and if you have insurance, try to get a head CT with contrast and maybe even an EKG to give yourself assurance that whatever you have, it is not potentially fatal. I don't mean to sound too morbid, but unexplained dizziness can freak people out because obviously your first worry is brain tumor or AVM, and then cardiac arrythmia.
can have devastating consequences...
Oh, what studying for this test will do to you! 
