heart palpitations thyroid issue?

I have had heart palps for about 3 years. I know it sounds stupid but I didn’t know what they were until about a year ago. I had a lot of blood work, wore a 2 week holter moniter, had an echocardiogram and the results were all normal. The holter showed the palps but they weren’t from an abnormal origin. I did find out I have hashimoto’s thyroiditis. An autoimmune disease that attacks my thyroid. Now I live in a small town with not the best healthcare that’s why I am here posting. I went to an endocrinologist who didn’t want to give me medicine but my pcp thinks I need it so for almost 2 months I’m on .25 of synthroid. Worked great at first but I am having palps again, I called my pcp she gave me more bloodwork but it all came back normal so she won’t increase my synthroid so I tried on my own to double it I felt great but I can’t keep that up I will run out of meds. So what should I do now? Look for yet another doctor, suffer with my palps? I am going crazy here!