I had an episode of acid reflux, followed by a cough (mostly unproductive) for about a week, then I caught a cold with sore throat. Sore throat lasted about 2 days a went away. Lots of coughing and sinus congestion. The persistent cough has now lasted for about 18 days(including the acid reflux episode). I have been on an antibiotic for about 4 days but the cough still persists. Do I need to be worried about this?