Wish me luck! RI

Ugh, everything started out so well with my guy! Somehow, he's gone from apparently good to RI in just a few days. The vet is finally open tomorrow, so he'll be going in first thing.

I am just amazed at how quickly this has progressed. The first day I got him (last Wednesday), I didn't notice anything and he ate for me. Three days later (Saturday), he defecated and I took him out to clean and spend a little time handling him, and he was pretty calm and curious. As I was handling him, I noticed some popping, a little mucus, and what seemed like a lot of yawning. Today (Monday) he's now gasping and blowing bubbles! I feel awful and I'm just stunned that he's taken such a quick turn for the worst.

I imagine part of this is my fault, as I was following outdated info in a book I got several years ago. I just picked up the book by NERD, and made the corrections needed. The humidity was low for the first two days I had him, I've since raised it, but it bounces around a bit from 75-80% after spraying to 55-60% by morning. The only other problem is that my night drop was too much thanks to the old book.

Could those two things have caused such a rapid deterioration in his health, or do you think I got him sick from the store and just made it worse with my inexperience?

Being a noob sucks at times!