Around a week later I took the same dose again (the rest of what I had) to help process the trauma. (It did help. I of course avoided the situation that made me faint the first time)
I'd want to try psilocybin again sometime; it's quite a bit more expensive than LSD but it does have an interesting profile (for me: less stimulant-like)
That fainting episode wouldn't have been prevented with a guide unless they followed me into the bathroom, since for some reason the smell is what caused me to faint. (I found this out during the second time when going near the bathroom made me feel fainty -- I am glad I figured out what it was so that I could avoid it. It would've sucked to conclude that I can't have psilocybin at all, or something)
I will actually end up visiting the NL for other reasons eventually, so I might look into magic truffles :)