Does anyone possibly know why my heart continues to stop for 5 to 10 seconds?

i have had a palpitation for years now and up until a few weeks i suffered no side affects. A few weeks ago while standing in my shop my heart stopped. i had not been doing anything strenuous when it happened. i started to feel really funny and within 5 to 6 seconds i started to blackout and fall. right as i fell forward i felt my heart hit really hard in my chest. after that my heart rate double. This has happened 3 times now and i'm worried that the next time it decides to stop, it will not start again. can someone give me an idea on maybe what is wrong.