unfortunately, antibiotics rarely work for sinus infections, especially if there is an underlying structural issue, or if the sinusitis is caused by severe allergy.

Inflammation is not evidence of infection. The only way to 100% determine an infection is to do a culture (endoscopically). CT scans can indicate an "air fluid" level that may mean infection. CT scans are the best bet, however, because they can show structural issues that might need correction.

Which antibiotic were you given? Some are dangerous (Levaquin, Avelox, Cipro).

Try an irrigation routine, Sudafed, and a powerful antihistamine like Chlor-Tremiton. chances are, the sinuses will clear.