I also say GO TO THE DOCTOR. I get headaches that last anywhere from 3 to 7 days. After an MRI, ENT doctor, allergist, a variety of migraine meds, my doctor sent me to a neurologist. He set me up with a couple of different prescriptions - sometimes one works, sometimes the other works, sometimes neither one helps. My doc keeps threatening me with a preventative, which I'd have to take every single day. NO THANKS! Oh, and my chiropractor tried, and a friend lent me a magnet neck wrap.

Anyhow, get it checked out. Especially if it has happened more than once. It is allergy season now, so maybe that will be the issue. It is far better to rule out the nasty stuff, and find out that it is something minor.

Also, +1 on dehydration. And the sinuses.

The neurologist told me that there is an entire spectrum of headaches, ranging from the classic tension headache to the classic migraine, and most people fall somewhere in between.

Good luck.