I wonder if I jinxed myself when I wrote my post about the breathing thing. I had it last night and didn't sleep much at all. But I checked my calendar, and last time it happened at the beginning of January was right before my period, and I am currently due to have my period in a few days.
I also have a cold, but even with that complication, I could tell that I was "forgetting" to breathe and having that sensation. My lungs are clear, so that's not the problem.