Would a Doctor Help me please?

Urinary tract infections don't always show symptoms until the infection has advanced, so you could easily have an infection without knowing it. You are way better off going into surgery after taking antibiotics you don't need than skipping antibiotics that you actually need. You can call the surgeon's office and inform them that you will still be on antibiotics a the time of the surgery and see if this is a problem, and also ask about the Azathioprine.