it isn't the laproscopy that has made you overweight
,sometimes Thyroid patients report weight gain if it is under managed. Get T3,T4 TSh levels of serum done and report to an endocrinologist
. Your dosage of thyronorm
may be modified although apparently it seems the right dose.Your Doc.may advise for avoiding fat meals and easy exercises,walking, cycling,jogging within your limits, cutting on calories as well and might explore hormonal
causes also for continuing weight gain if unrelated to diet and under-movement or exercise.