You have not mentioned since when you are suffering from tuberculosis
and since when you started taking anti tubercular treatment.
Extreme weakness is mainly due to uncontrolled diabetes
and partly due to tuberculosis.
It is very important to control your diabetes for effectively curing your tuberculosis.
Anti tubercular medicines prescribed are absolutely right.
Take proper anti diabetic medicines in proper doses to control the diabetes.
Be regular with your doctor for effective control of sugar along with necessary dietary precautions.