Hi,
How are you? It is good that the tests done were fine. Vertigo and dizziness can be caused by ear / eye problems, blood pressure. and other underlying medical condition such as anemia and low b If the cause is not yet known, try to avoid driving and other activities that may harm you. Have this evaluated further by your doctor for proper management. A tilt-table test, as Dame pointed out may be helpful as well. Take care and do keep us posted.
I would definitely go see a doc. If you've got semi-random pre-syncope/vertigo going on, something is definitely off. I would randomly lose consciousness for the longest time until I had a tilt-table test done, and we found out that I have vaso-vagal syncope. Now that I'm properly medicated, I don't pass out anymore. If it's 'just' vertigo, and not pre-syncope, that's still big and needs to be addressed.
Good luck and keep us informed,
~Dame