I have had similar problems recently and have completely excluded all stimulants from my diet. I also aim to go to bed at 9.00 and avoid stressful or tiring situations. I also avoid highly processed food and choose organic food where possible. I am much better than I was. Hope you can get relief.
Research Histamine Intolerance. That is how I found the answers to my racing heart issues, heart palpatations, breathing issues, etc., Jost doctors don't know about it, and therefore would not be diagnosed.