Should I Go Back to the Doctor?

About 2 weeks ago I went to the doctor because I had a cough for over 2 weeks. She gave me a tuberculosis shot thingy and it came out positive.

But I got chest xrays or whatever and it came out negative so she said in a month i'd go back and get another tuberculosis test.

The thing is its been about 4 weeks now and my cough has been getting a little worse and I still have alot of phlem coming up.

Do you think its normal for me to still be coughing? Or should I go see my doctor again?