Hi there.. thyroid is endocrine gland which secretes thyroxine hormone which is essential for growth, metabolism and other functions of body.. Hypothyroidism means that there is less synthesis of thyroxine hormone( due to iodine deficiency, pituitary causes, infection or autoimmune disease of thyroid gland) which leads to weight gain, weakness, easy fatiguablilty, loss of appetite.... treatment of which is thyroxine supplements in form of tablets.. you have to take it for lifetime.. you can continue with same dose.get tsh done once in every 3months to check on whether the dose given is enough or needs to be increased or reduced.. please do regular workout like brisk walking, jogging.. avoid foods like cabbage,cauliflower, raddish, broccoli as they known to reduce thyroid hormone synthesis in body, use iodised salt only..hope this helped you..