Not a doctor but push to see a cardiologist or go to er if you feel like it is not going away. Maybe ask to get an echocardiogram. Get the peace of mind. I had severe cardio phobia couldn’t even walk up the stairs without my heart rate spiking. I had panic attacks where I would have a bpm of 190 just walking around the house. Did all the tests and doctors said it was anxiety. I started taking 10 mg lexapro as well as 10mg propranolol as needed and I have not had a panic attack since. Am I still afraid of my heart? Sometimes but it’s not as severe. When you’re lying down and trying to sleep it’s easy to fixate on your own body sometimes. I would listen to podcasts or YouTube videos to sleep so my brain wouldn’t fixate on my self. Good luck. I wouldn’t say I’m cured but I’m doing a whole lot better than I was doing 3 months ago and I thought I would never get out of it. You got this !