I've had the palpitations, too, and have had lots of heart-related tests over the past several years to rule out every kind of heart problem you can imagine. Mine have been attributed to anxiety, and possibly perimenopausal symptoms. It never hurts to see the doc, especially if it will help you to know that you are in good health. I know it is so aggravating.....but try to relax in whatever way you can, and take deep breaths, and know that we support you.
P.S. I agree with Josey....looking up stuff online is usually not a good thing for those of us with anxiety.....IMO. Take good care, and get some rest if you can.