I have had BPPV twice. Each time I had no luck with eply procedures and just let it run its course until it subsided. Each time it was in the winter between mid November and mid December. Each of these times of the year are of course when Vitamin D (supplied from the Sun) was at its lowest in my location. I believe the vitamin D link is real. See more here and noticed that in this study Vitamin D stopped vertigo episodes:
Vitamin D deficiency and benign paroxysmal positioning vertigo. - PubMed - NCBI
Per that report the following is reported:
"Vertigo attacks did not recur after supplementation with vitamin D"
I'm just trying to help you others as vertigo due to BPPV is an aweful and quite terrifying feeling that causes massive desperation. But the reality is that you can get better - just increase that Vitamin D and in the interim try not to move your head as much as possible.
Best wishes to you.