I have an upper airway infection that came back after completing antibiotics. i am now on a second course, 4 days in with little improvement. is this because i have a weak immune system or has the infection become resistant to the medication?

Symptoms: If you are producing sputum, it may be analyzed to determine the type of bacterial infection that you have and the resistance pattern. A fever and continued sputum production indicate that the infection is not well controlled. A chest imaging study may be obtained when you see your physician. Rest, drink fluids and use nasal saline spray.