Welcome to HCM,
You are going changing antibiotics is not fare, by doing this there is chance of developing resistance against antibiotic giving short time relief.
It is better to go for x-ray of sinuses
and and find out the reason of not clearing sinus infection
Consult ENT surgeon and if require he will go for sinus puncture and drainage
of pus or exudate from sinuses will clear the sinuses.
Mean while go for Vicks vapor inhalation.
and cold exposure.
Ok and bye.