Hello,
From the clinical features (as you said), its look like
hypothyroidism. But obviously, I need to see the lab result including T3, T4,
TSH level. So, if you can say these levels, it would be easy for me to say.
Anyway, maybe the doctor has noticed something about the level of thyroid hormone, so, prescribed you have
Synthroid.
It may have the lab result is normal but the thyroid hormone levels are bit low, maybe not below the normal.
In our medicine practice, we have to consider person to person variation.
May be your thyroid hormone levels are normal (low - normal) but given your clinical feature (signs and symptoms), we should consider starting a medicine for hypothyroidism.
So, the doctor has said to you to start. If you still not without confusion, feel free to post your thyroid hormone levels and ask another question.
Hope I have answered your query. Let me know if I can assist you further.
Take care
Regards,
Dr Dipan Samanta, General & Family Physician