Was This Snoring or an Allergy Attack?

[laurie]

Sadie Jane, my 12 1/2 year old German Shepherd mix just had her senior check up. All her tests came out in normal range for her age. She takes Proin for incontinence and has for about a year. Last night she woke me up with this very load breathing noise. Her mouth was not open just breathing loudly through her nose. I jumped out of bed. sat beside her, her eyes were open, I talked and and was checking her. She layed there for a few seconds then got up and walked out the dog door like nothing was wrong. Short time later she came back in, got on her bed and went back to sleep.
I thought my dog was dying for a minute. could she have been dreaming? Could this have been snoring or an allergy attack as we've had a windy night? It startled the heck out of me. Of course I will contact her vet but are the above listed possible?
It didn't last long at all, a minute or two? Like I said, when I heard her,I jumped out of bed so quickly, and was still disoriented from waking up.