I Had A Sinus Infection About 3 Weeks Ago. Had

I had a sinus infection about 3 weeks ago. Had to go to the Dr a couple of times for antibiotics. Had a CT of sinus done that was negative. Now I have had a headache for about a week. Have also been to the emergency room a couple of times with a repeat CT scan. Have been given several different kinds of medications for the headache but nothing is helping. What do you suggest.