It's anxiety, this has happened to me a few times. It COULD also be sleep apnea, but i don't think you would all of a sudden just get a symptom of that now. I would wake up and just feel like i couldn't catch my breath or breathe, and this causes me to jump up out of bed and makes me even more neurotic. and of course NOW that i always think about that before bed it seems to happen more and more.