I had a total thyroidectomy and am now taking .137 mg synthroid. I have always worked out faiithful minimum 5 times a week for minimum 30 minutes in the morning before work. I generally power-walk with 3 lb weights, do eliptical or treadmill with 3lb weights in an effort to raise my metabolism. Now, I have been gaining weight and wonder if NOT having a thyroid means I can no longer increase my metabolism to burn calories? any suggestions