Hello, Thank you for using our service. A Tsh level this high will contribute to lethargy, low energy, and weight gain. Treating a thyroid problem can be tricky, but hopefully the medication will suffice and your TSH will come down. As you thyroid begins to function better your energy should increase thus you will expend more calories and weight loss should occur. Make certain you are giving your thyroid the nutrients it needs such as iodine, tyrosine, vitamin C.There are others, but these are the most important. Tyrosine is an amino acid and although you can get it from food if you want to use it to boost thyroid you take it as a supplement on an empty stomach with vitamin C. Iodine is deficient in many geographic areas and is why there is iodized salt. Make certain you have enough of this or your medication may not work well. I hope this helps. Thank you so much for using our service. Kathryn, MS,RDN