I've got short but severe pain in my head, what should i do?

Get an immediate: Evaluation. There is no way to tell what it might be. Consider yourself fortunate to get a warning sign. I personally would go to the nearest hospital. Have someone drive you. I would not drive myself. Once some basic tests are done, you can relax, and address the possible cause. But for now, there is a problem, and the causes are far ranging, some lethal.