(LOVE your screen name.....he he he)
You fall within the normal range for free T3 level....almost smack-dab in the middle. The normal range for free T3 is 2.30 - 4.20.
Your low TSH level is probably the reason for your doctor decreasing your thyroid supplement. Low TSH can indicate Grave's Disease (over-active thyroid) also known as hyperthyroidism therefore reducing the dosage is appropriate.
Although I agree with your doctor that your dosage should be lowered, if you find you are having a lot of the tiredness that you mentioned above, go ahead and contact your doctor. The low TSH itself could be responsible for your tiredness rather than the lowered dosage causing it.