Hi
Vertigo just means dizziness. So you were dizzy. I was too last night after a party.
We would need to know a bit more - what were you doing, how long it lasted, any other symptoms, did you fall over etc etc. Then what other medical issues you have and the drugs you are on. And finally we would examine you - cardiovascular, ENT - especially examining the middle ear.
I am sure your doctor did all this and it justifies him taking this action. On the whole isolated dizziness without falling / loss of consciousness and no medical history or findings would be a 'watch and see' for most doctors
godd luck