Hi,
I'm sorry that you are struggling again with these anxiety problems. I do understand the fear you are feeling over your heart symptoms. I, too, have the fluttery, missed heartbeat stuff and it scares the life out of me. Although it sounds like you had a panic attack, I wouldn't give up on going in to the doctor to be sure of what is going on. When can you get the results of the ekg? Waiting for test results is the worst, I know, it gives you too much time to think negatively.
I've been panic attack free for quite a while as well, but every once in a while, one will just hit me seemingly out of the blue and throw me for a loop, and I don't think that is uncommon. Try to keep your thoughts positive for now while waiting for your results. If you don't trust this doc, maybe see another one? It's better to be safe than sorry, and to have solid peace of mind rather than room for your mind to run wild with scary thoughts. Hope you get some answers soon!