Hello and welcome to the Heart & Cardiovascular Disease Forum. I have no personal experience with your symptoms. It does concern me that you posted, "Now almost exactly a year later I have felt fluttering again and the sensation that 1) I am really tired frequently and 2) that my heart is going to pump right out of my chest."
I believe this warrants a visit to your Dr. for a medical screening exam. I think you will feel better if you talk with your Dr. and some tests are done. Please do advocate for yourself and reach out to your Dr.
Hopefully another member may have input that will help you.