Non stop coughing! Help!!

So from about week 30 to now (33) I’ve been coughing non stop I went to the doctor he said it was a cold not my asthma told me to do over the counter stuff.. 2 days later they called to see how I was doing.. STILL coughing so he wanted to try a prednisone burst which did nothing... STILL coughing! I’ve been doing everything... honey, lemon, humidifier, fluids, allergy medicine.. next stop is the suedafed! Any other ideas would help! Is this going to last for the next 7 weeks??