Have you had sinus issues in the past? I think my suggestion would be the same as Nan's. . .no one actually enjoys going to the doctor, but a headache could be symptomatic of so many other things, that unless sinus meds are actually doing something, it might behoove you to "woman up"
and make a Dr. appt. just to make certain there's not something else going on. Hope you feel better soon, hon!