Welcome to HealingWell. A heartbeat that is occasionally irregular usually is not a concern if it does not cause other symptoms, such as dizziness, lightheadedness, or shortness of breath. The skipped beats you are noticing are known as ectopic beats and they can be very annoying.
It would probably be best to have a complete round of tests done on you - ranging from ECG/EKG, echocardiogram and stress testing, the latter two if necessary. There are also other specialist tests that your cardiologist can adminster if he/she finds anything of concern in the ECG/EKG.
Bottom line is that once you're assured by a doctor/cardiologist you can trust that there is absolutely nothing wrong with you, stop worrying about it! These things can appear suddenly, and they *can* just disappear just as suddenly. The less you think of them, the better for your mental and physical health.
Again a warm welcome to HW.