Do you have a slight fever with it? I just got over what was, most likely, a sinus infection. I always have a headache with that.
It wasn't bad enough to get to the Docs for anti-biotics, but, in the past, E-Miacin type antibiotics would knock it out almost immediately. Peniccylin(sp) or amoxicillian, wouldn't touch it.
You should get yourself to a Doc, ASAP, because yours is hanging on. Pain meds are nice but that's not going to make an infection go away, if you do have one.
Feel better soon. Headaches of any kind are hateful.