Another neck question

I have had 4 conflicting diagnoses in the last yr and a half (BPPV, cervicogenic, chronic subjective, and MDDS), after 3 yrs of gradually worsening, and otherwise waxing/waning symptoms. No previous neck injury or neck pain; just gets a little tense at times. Last spring, my PT suggested I had sustained poor posture at my office job all these years, which could have caused cervico. Seems laughable now that i think about this. However, one incident that happened last summer still confuses me. I was watching a movie laying down on my floor, on my back, but I had my neck propped up in a funny position on a bean bag. Felt fine during the movie, and when I stood up, but I took a nap later that day and woke up HORRIBLY dizzy (rotational and floaty feelings). Took a few days to recover! Is there ANY way whatsoever this could be cervico, or could MAV have been linked to this experience? I have mild positional vertigo some days, but it is never the horrible room spinning sensations that BPPV-ers describe. Dix Hallpike was normal twice.

This link provides causes of BPPV, (third section) It lists head in a position for long time like for a dental procedure…maybe you experienced something similar.