Hi there I understand your concern...it depends upon underlying cause resulting in hypothyroidism...you have not mentioned anything regarding treatment history...I would suggest to get immediate
thyroid profile done and consult nearest physicians...weight gain is one of the symptoms of hypothyroidism...avoid junk foods,carbohydrates like rice etc,avoid oily foods...add proteins and fibre rich foods to your diet with green tea,green leafy vegetables, fruits...do regular exercise at least 2 hours a day...good luck.