Medical Questions? Ask a Doctor Online!
It sounds that problem relates to you being off Synthroid for three weeks ..
Feeling cold is symptom of too little thyroid hormone which regulates your metabolism ..
I advise that you take your SYNTHROID consistently each morning ...
After 6 weeks get a follow up check on your TSH
I hope that this is helpful for you
Let me know if I may be of further help
If my answer has been helpful and to your satisfaction then please remember to leave positive feedback
Thank you and Best Regards,
Anthony Bray MD