Do you have a notebook or calendar that you record these things on for future - so if it happens again?
sometimes weird things just happen.

I had some really weird dizzy spells and fast heart beat in 2005 - lasted about a week and a half, on and off, went to a naturopath and she did tests and full blood work, by the time the results came back the symptoms were gone. The tests were all OK except high chol & triglycerides.
She decided that it was just a very odd bug of some sort- even tho no fever or ill feeling other than the slight nausea & fatigue during the dizzy spells.