Posted 10/2/2014 8:23 PM (GMT -6)
A low TSH is usually present with hyperthyroidism, not hypo. Did the doctor also do a free T4? Medication adjustments should be made from that rather than the TSH, which is produced in the pituitary gland.
The actual dosage reduction your doctor made is very small, and shouldn't cause any problem in the short term. You should be scheduled for follow-up in about three months, with TSH, free T4 and T3 done at that time. When you get those results, if you post them here along with the reference numbers, we can probably help more.
Changes in thyroid function do happen, but very slowly. I had been on the same dosage of levo since my RAI treatment for Graves disease 22 years ago, and just three months ago it had to be increased a bit because my levels were low. Many things can affect it, including hormonal variations.