Hi I Have A Question, I Hope It Will Clear

Hi i have a question, I hope it will clear all my worries about my health problems, Back on the 31st of December 2015 I was not really feeling well, I got a mild fever, a swollen throat, difficulty in swallowing, and a mild cough, But the thing that worries me is I cough a streak of blood on the 2nd of January although It's just mild like it happens thrice in a day sometimes twice or once for 4 days and it was very small amount like less than a drop of blood. I went to a doctor on the following day and they have me tested with Blood Test and X-ray and was diagnosed with Upper Track Respiratory Infection, The Doctor told me that there was no sign of abnormalities in Xray as well, but I got bacterial infection on my blood. The doctor told me to take Clarithromycin for 7 days, and other medicines for my cough, So far on the 5th day that I took the meds I never experience the coughing blood again, and no fever at all, It feels like Im back to normal again.

Now my question is, Am I risk for a Lung Cancer? I am 31 years old, Male, I've been smoking for 13 years, maybe 5 -7 sticks per day.Havent got any relatives with Cancer. No sign of abnormalities found in Xray result. Diagnosed with bacterial infection on my blood and Upper respiratory tract infection. I hope you can help me out clear all my worries, Thanks a lot