Is the rhythm regular or irregular, is your pulse fast?
The vast majority of palpitations are ventricular ectopics, early beats originating from the bottom of the heart - they can feel like a jump/skip followed by a hard beat.
They are mostly benign, so they feel odd but aren't going to harm you and normally don't indicate underlying heart disease.
Lay off caffeine, especially in nasty crap like red bull and monster, but also coffee and tea