What your feeling is what everyone feels at sometime or another, it just that some of us have a hypersensitivity to them and we feel them alot more and mostly during a rest time. Have a check up to rule out anything abnormal and dont let them scare you, they actually will become more irritating than anything else once you rule out any underlaying problems. Watch for triggers, that make them worse and happen more often. Talking about always makes me feel better when they get scary. Good luck.
What exactly are you feeling? Are you concentrating your whole day on when you heart isn't going to properly beat? Quit doing that! Just some advise.... YOU ARE OKAY. :) Lots of people experience this. As a challenge for you, and as it is a challenge for myself., TOMORROW!, -- try not to worry how your heart is beating or performing. Lots of members here experience these sensations the are so overwhelming. We tend to over emphasize after we feel these sensations for either the first time or for long periods of time, and we panic. Panic & Anxiety are top percentile of abnormal heart rhythms. Hope this helps. Zach