Hi, Welcome to Health care magic forum.
As you describe, you are a patient of
hypothyroidism, as you are in 20's there is a possibility of increased usage of the thyroid hormone, so the dosage of
thyroxine you are using may not be suffecient for your body. That may be one of the causes.
You can keep weight under control by minimizing the intake of calories, fats,fries, junk foods, and oily foods.
Increase your activity by practicing morning walk,
yoga, gardening, and do any work in front of you.
Minimize the sleeping time ,practice late to bed, and early to rise, avoid day time sleep.
Wishing for a quick and complete recovery. Thank you.