Posted 7/1/2016 9:42 PM (GMT -6)
Hi and welcome to the forum,
What is your dose of Synthroid ? for how long have you been taking it ? What are your lab values? specially TSH ?
Palpitations are more common with hyper but are possible also with hypo, so are anxiety and panic disorder.
Were you tested for Hashimoto's disease ? if not, then you need to be tested for TGab and antiTPOab, if either is positive then you have it and it is the cause for your hypo.
with hashi one will need to increase the dose of Synthroid each about three months based on TSH.