I have had a cough for about eight weeks now. It's just a dry cough, and there's no other cold symptoms. After three weeks, I went to the doctor and was prescribed antibiotics, but two weeks later, I still have the cough. I then tried allergie medicine, but that is not working. The cough is dry and I don't really feel an itch. I often get into fits of coughing for a bit and then stop. I cough way more when I am up and walking around , and when I sit down for a bit, I don't cough at all. What is this ?