Tuberculosis Dr. I am a tb patient i've completed my 6 month course of medication and in chest xray after 6th month there is nothing found but my Dr. Prescribed me to carry my medication further three months ..why? directly 3 months why not 1 or 2 months ...following this I also want to ask that I always feel thirsty even after drinking water and most of the times after waking up from bed I feel my head gets heavy and then gets normal after a couple of seconds why all these things are happening?