I DO have all the symptoms of hypothyroidism- weight gain, extreme fatigue, etc etc etc. The doctor just keeps saying to 'diet and exercise'. Trust me, if I had an energy I would exercise, I used to go to the gym five days a week,now all I want is to sleep.
If you are not feeling any symptoms, stick with what the doctor tells you unless you begin to feel abnormal in any way then get back to the doctor.