Antibiotics, immune system, and sinus infection

Hi everyone. I have a question. My allergist did a sinus X-ray and said he thinks I have a sinus infection and need a 21 day antibiotic. I have already taken two courses of antibiotics this year and two courses of oral prednisone so I am worried about my immune system. If it did work and help me feel better it would be good. Anyone have any advice on whether antibiotics will help? Is it possible breathing issues and some wheezing could be due to sinuses?

Thanks Razzle. Is there any way to find out if my infection is bacterial or viral or fungal?

Sometimes an analysis of the effluvium from a sinus washing can tell what kind of pathogen (if any) is the cause of the trouble, but not always. Doctors at Mayo Clinic did a study and found that fungal sinusitis was way more common that previously thought, but they looked at actual tissue samples taken during sinus surgery (adnoid removal, etc.) instead of just the sinus washings.
Alternative practitioners can sometimes use applied kinesiology (muscle testing) to determine which type of infection a person has. This method is about 70-80% accurate if the practitioner is experienced.
Another method for determining the pathogen type is a trial of medication - antifungal for a bit, then if symptoms don't clear, move on to antibiotics, etc.
In any case, it would be good to discuss options with your doctor to see what he says and if he thinks one or another may be more likely (he may have gotten clues from details discussed during your appointment, etc.). Or he may have another idea for how to determine what type of pathogen is the culprit.
I hope this helps - take care,