about two weeks ago, i started waking up every night, not sure what causes me to wake. but, while i am laying there, my heart stops beating for a second and then restarts as normal. it will happen about three or four more times and then i eventually fall back to sleep. and then two nights ago, every time i go to lay down i get a horrible headache, when i stand up, it goes away. so, i was just wondering if i should be worried?