Hi. I've only just seen this, so sorry for the late reply. I could write a book on skipped beats as I suffered with them massively after I had an operation about 15 years ago. At times I would get them constantly and for years I had them on and off for days at a time. They caused me huge anxiety and panic attacks (which can make them worse).
The good news is they are often benign, though obviously alarming. But as others have said the most important thing is to get them checked out asap. Heart arrhythmias are usually easily identifiable on ECG machines and once you've done the stress test they will know what's going on with you and how to proceed. A 24hr holter monitor would be helpful as it would record any that you were not aware of - most people will get a few during the day. Even in my case, where I was having thousands a day, if they are benign the most likely route will be to simply ignore them (not easy) or go on beta blockers.
Without sounding alarming, I am sure your gp will have mentioned that you need to be concerned if you start suffering from dizziness or blackouts, shortness of breath, chest pain. I've had a few trips to A and E when my heart has been racing and beating erratically. It's always calmed down on it's own but it's always better to be safe than sorry. Best wishes.
Edit: I would avoid caffeine and alcohol until your appointment as many people find these trigger palpitations. I only drink decaf now, though in my case it was as if my heart had got massively oversensitised and loads of things could set them off, including cold weather, hot baths, overeating, anxiety.