I can't imagine your doctor would pass on personal medical information to immigration (unless the examination is part of an immigration physical). They do have a duty to report communicable diseases like TB to Public Health and will discuss this fully with you. Your case will most likely be followed by a Public Health Nurse who will do the test, provide support and pills which MUST be taken daily for a specific period of time, even when you start feeling better. It is essential to get checked out. You may not have TB, but without being tested you will continue to worry. Testing for TB is not difficult. You may have a little skin prick on the inside of your forearm which the nurse will examine within 72 hours. Or you may just have a chest x-ray. Make an appointment tomorrow and tell your doctor your concerns. It is the right thing to do. Good Luck