What Causes Recurring Fever,ear Pain And Sinusitis?

I m wondering if I was put on the wrong antibiotic, I m a 66 year old female, I feel fine in the morning but every evening the fever starts. (( 99 to 100.4) the minute Clinic at CVS gave me a antibiotic (3 Large Pills) but still the fever comes, and some days the ear really hurts. I do have constant sinusitis , and right now I have a occasional cough for drainage…