Hi Judy. It sounds like jsut anxiety/panic symptoms to me. You did the right thing by going to the doctor and doing tests on ur heart. U said that "nothing seems to show up"........maybe thats because nothing is wrong with your heart!!
Believe me, i have done this before too, and i'm still thinking negative about this too. But we gotta be a bit more realistic about this....we have to remind ourselves that we already have been to the doctor and did tests, nothing is wrong, thank God!!!! So we just gotta stick with that. Try challenging all these negative thoughts about your health. U already checked it out and you are perfectly healthy!!! Maybe its just the anxiety!!!