Leo, did you feel yourself move or did remain stationary and your surroundings move around you? I was told that if you moved its likely to be a ear problem, if your surroundings moved and you remained stationary then its likely to be a neurological or Neuro-otological problem.
In my own case it has happened for many years but fairly irregularly. If you do report it as long as you are symptom free you should just get a multi crew restriction once you have been symptom free for 2 or 3 months.
If it keeps happening it may be worth seeking a docs opinion as initially some of the potential things I was investigated for as a cause of my vertigo I was glad I didn't have!!!!
It sounds likely though that it was associated with the movement of your head. It could be just an ear infection or something called BPPV. This normally happens after raising your head and looking down. If it is something like this it really could just be a one off. Unless it keeps happening and as your symptoms were very short I wouldn't panic. Chat to your GP though.