What Causes Extreme Fatigue, Weight Loss And Frequent Bowel Movement?

I am taking Synthroid 75 mgs. My recent blood test showed TSH .057 and free t3 2.65. Have also had antithyroid peroxidase reading of 58. I am experiencing extreme fatigue, have lost some weight, get winded easily and having frequent bowel movements. Am I taking too much medicine or not enough. Also, do I have Hashimotos? Feel no energy at all. Thanks for any advise.