I was falling asleed and jumped put of bed with a feeling like my heart stopped and i was going unconsious. i took my blood pressure for reassurence and it said 99/54. pulse was 92, then yook it again and pulse was 55. is that concerning?

It is difficult to understand exactly what you are experiencing. But as far as The heart rate goes, this number changes from second to second based on what is going on in the body and mind. Fluctuation from 55-92 is not unusual. If this continues to cause you distress, then I’d consider getting seen in person.

What is your usual resting pulse and your average BP? Heart rate and BP are usually lower during sleep. I'm unsure what awakened you but it wouldn't be your heart stopping. Rather a racing heart, caused by dreams or other factors, are the usual causes. If your back with your usual appropriate heart rates and BP, I would rest assured. If not see your MD or a cardiologist for an evaluation.