Suggest Treatment For Sinus Congestion

I have been suffering with head/sinus congestion for the past couple of weeks. The initial congestion was followed by a couple bouts of dizziness, nausea and cold sweats. I don't have a fever. Actually, my temp is below normal. I have been taking Mucinex D for the congestion and drainage, but am concerned if i need to be taking an antibiotic already prescribed, if I don't have a fever. What should I do?