Hi,
You need to review with your doctor and get a chest xray and preferably a blood test done.
This could be blood from your nose, throat, teeth and the exact cause and site needs to be identified.
Was it fresh blood? Was it mixed with mucus or sputum? Was there any associated cough? Do you have any dental problems?
You need to stop smoking immediately.
Let us know what your doctor advises and keep us posted on how you are doing.
Hope this helps.
Regards.
I am not a doctor but you should go to a walk in clinic or your doctor (if you are lucky enough to have one). Sounds like bronchitis or pnemonia. It never hurts to get checked and these two things do not go away on their own. Blood is pretty common with pnemonia