Hello and thanks for writing in
The causes for the heart palpitations in your case are:
1. Hypothyroidism: Get checked your Thyroid function test and adjust your dose of synthroid
according to that. Low or high doses can cause heart palpitations.
2. Anxiety: It is the major cause for this. Make your self relax and consult your doctor for medication and counselling
3. Problem in conduction system of heart like Atrial Fibrillation
A simple EKG at the time of episode or holter examination can get you to a diagnosis. Consult your cardiologist and go for investigations order by him/her.
Hope this will help you.