I've had that too, woke up feeling like I had been holding my breath, like a startle, usually just as I drift off. It comes and goes for me. It's never stuck around long enough for me to get in for a sleep study, and my wife says she didn't notice snoring or gasping. Rather odd, but I've never been able to get to the bottom of it.
I get that too. I wake up sometimes still feeling like I'm not breathing or wake up gasping and it is always as I am drifting off to sleep. ( I look at the clock and it always seems to be within the first 30 minutes after I lie down). It comes and goes. I can go months without it happening and then it can happen every night for a while.
Same with me, have had this happen on and off for 16 years! (since i was early teen)... Never had a sleep study before either!! But i do find these episodes happen when i am stressed!!
Hope you get and answer, do come back and let us know how it went..
good luck x x