Event monitor causing more stress

I am a 34 year old female with PPD and Hashimotos Disease. I had my first child 10 months ago. Have never had any health problems before having my son (except mild depression and anxiety/panic). Since having him I have felt the worse I have ever felt in my life. I do exercise, quit smoking when I found out I was pregnant, am not over weight, dont drink or do drugs. My thyroid has been over active now under active. Being treated with Synthroid which I don't tolerate well, makes my anxiety worse. Since all this started I started having episodes of fast heart rate. They first started when I became hyper thyroid, then resumed when I was put on Synthroid. It wakes me up sometimes. I have driven myself to the ER because of it. My Endo and now my Cardiologist both tell me these have nothing to do with Synthroid. I had a stress test that was normal, was told i am in good shape and everything looks good. I am now wearing an event monitor. When I jog it goes off automatically. This morning when I woke up I felt horrible, extremely fatigued, felt like I couldn't wake up. I was feeding my son breakfast and it went off automatically. I didn't notice any palpitations when it happened. Now I am freaking out that I have an irregular heart rate. Why would it go off automatically when I'm sitting still? Should I call the doctor? I'm very stressed about this whole thing. Please any advice would be great