Then follow the steps I laid out to investigate. Panic and stress can be so bad that it causes heart rythm disorders especially if you have been dealing with them for awhile. You may have atrial fibrillation on top of hppd or your stress is so bad it’s causing it. Like I said have a cardiologist do the things I laid out and if they find nothing. Focus on your mind. In a study there is evidence that extreme levels of anxiety, stress and even hypochondria can manifest as real problems. Long term if you don’t work on it, this may cause real health problems like hypertension, heart rythm issues, stroke. Your going to be okay just make sure your heart is okay with a cardiologist.