heart palpitations are common and usually completely harmless. it feels like your heart has stopped but it's actually your heart putting in an extra beat and because the rhythms changed a bit you notice it and it feels strange but it's nothing to worry about.
they say if you have more than 6 in a minute or if you have other symptoms such as dizziness, shortness of breath or fainting with the palpitations it could be something else.
it's probably stress and anxiety, i had them the last 3 days on and off and it is a bit worrying but you just need to tell yourself they're common and harmless, everyone gets them now and again.
just try your best to keep your mind off them because if you think about them you will be anxious and they can keep on happening.. i know it's hard but you just have to try your best to distract yourself