Hello Belle, now that is interesting about vitamin A - tends to support the notion that all sorts of things that we put in our bodies can have totally unexpected negative effects. I always think of supplements as innocuous can't do you any harm so may as well give 'em a try - not so, as CLKD points out. I'm so glad you got rid of the vertigo, it really is a bad thing to have.
Flan, I'm so sorry you're having to think about stopping HRT (I was with you on that one half way through 2019 and again recently, kept having such problems finding a product that worked that I spat the dummy and decided to stop. Unfortunately every symptom that I'd already experienced first time around plus a few new ones decided to turn up again). Mind you it may be no bad thing to do a reset as you say, just to see what's what and gauge just how intolerable the symptoms are. Having said that, it is taking me ages to get the estrogen levels up again and I'm concerned I've done damage in the meantime (joints and muscles amongst other things). Good luck whatever you decide.
Crispy Chick, I'm sorry to hear you had such adverse reactions that kick started your peri. It's not exactly one of the more common symptoms so you wouldn't know what the heck was going on would you? I'm pretty much in agreement with you that hormones are somehow involved, regardless of whether the vertigo is the ubiquitous (and one trick pony diagnosis of ENTs and the like) BPPV, or something else. You got to wonder though which hormones, and what levels? I've researched and researched (as you do, given that three plus years is plenty long enough to get the googling down pat) but found very little in the way of concrete findings regarding causes/catalysts for vertigo. Lots of speculation and supposition...