Hi. That’s so disorienting! Glad you weren’t alone!
And yes, it’s happened to me, too.
I’ve had a few spates of fainting spells over the years. They come in clumps; once I fainted 4 or 5 times over a period of a couple of weeks, but didn’t faint again for several years. I fainted in the shower a couple of times (and have since renovated with a shower bench and multiple grab bars). But the most common way I fainted was when getting up in the night to go to the bathroom or respond to my kids’ cries. Twice I woke up on the floor as if I’d been sleeping there, and I had no recollection of going down (so it must’ve been really quick)!
My neurologist didn’t think it was MS-related, and instead suggested heart work ups including an overnight holter study. Thankfully my heart was fine. But the specialists decided I have a form of circulatory disregulation. Apparently my blood pressure sometimes dips without warning. That makes sense, as I’ve had trouble since my teen years (I’m now 5😎 with getting grey outs when I stand up too fast (this is where your vision goes black, and it sounds like you’re underwater, but you are awake). And although I’ve always loved roller coasters, it was just a few years after my MS was diagnosed that I began blacking out if I went upside down in a roller coaster. (My doc at the time said it was just that my “elevator switch“ didn’t work.)
The “treatment” for the circular dysregulation was simply to drink more water, and to increase my salt intake a bit. And to be honest, I haven’t really fainted much since doing that (but I have gained to weight post-menopause, lol).
And although my neurologist still thinks it’s unlikely that this has anything to do with MS, I really do wonder. Certainly the brain controls circulation and so it would make sense that if it’s not regulating properly, that could be a problem caused by brain lesions.
I also think it could be related to the recurring vertigo that I get. This is thought to be more likely related to MS, as people with MS apparently get vertigo more than the general population.
Anyway, I hope that helps and isn’t too much information. Good luck with finding out what’s going on with you, and hopefully it won’t happen again!