You are hypothyroid as your TSH
As your hormone levels are low,you will gain weight.
%0micrograms of thyronorm
may not be sufficient.Please increase it to 100 micrograms with the consultation of your doctor.
Your symptoms will come down.
Your sleepiness is due to hypothyroidism
You may be having Hashimoto's thyroiditis
.But,it has to be confirmed with FNAC(Fine needle aspiration cytology)test of thyroid only.
Increase your thryonorm dose and get TSH levels checked regularly.
You will be alright
Nothing to worry
Wish you good health