I'm currently enjoying my third sinus infection in three months.

I'm going to the doctors tomorrow to get some antibiotics but i was wondering if anyone knows of anything i can take to maybe boost my immunity. Clearly my immunity sucks.. my dad got a cold last week and of course, i caught it too.. but i find i don't just GET a cold... i get sinus and ear infections too. My aunt thinks perhaps i have allergies and they build up within me until it becomes an infection. i don't know much about allergies so i don't know i that even makes sense

anyways. .any suggestions would be wonderful!