In fact, I don't do it unless I fall asleep on the couch without my cpap, or if it comes off during the night. But I remember the jerking when the breathing mechanism in the brain kicks in after the apnea (apnea means no breathing, it is considered to be when you don't breath for 10 seconds or more)
Of course I realize this may not be your problem, but it was mine. It scared me to wake up so panicky.