Why am I getting dizzy at night?

O.K. – here’s the story. I often get stuffed up ears and a nostril, particularly on my left side, from allergies. If I sleep on my left side, I sometimes get a headache there, too. For the last week or so, if I sleep on my left side and wake up in the night, I am a little dizzy. I know I could go to the doctor and will if it persists, but it seems such a nebulous thing, that he will probably dismiss it. Anyone have any ideas? (Hearkat?) It feels to me like it is related to the allergies/stuffiness. It is not labyrinthitus – I’ve had that and that’s much worse. Thanks for any broad, speculative suggestions.