Hypothroidism is a big deal. The basics are in the link below. If you are under 30 and after the your thyroid is straightened out and time is given for your endocrine system to balance and still test is low and symptoms do not improve I would recommend a restart (also in the link below). If you are over 30, or a restart fails, then TRT will be the only route for symptom relief. However, get the thyroid resolved first.