I appreciate everyone's input and concern. Obviously, she is the most important thing in my life and I would do anything for her to make sure she isn't suffering physically or emotionally.
In any case, the situation seems to have self-resolved. Basically, since the day after my last post, things are back to normal; before I had any opportunity to take her to the vet. Me and my gf still have residual PTSD from her water habits, and if we're mid conversation and hear her go to the water dish, we'll stop and listen quietly to see if it's normal drinking behavior (and it has been normal since).
While it might have been medical, it also might've been behavioral; I have been making it a point to have her downstairs in the studio with me more often and have been making sure to give her extra attention.
Anyway, she's fine once again, but I'm gonna remain vigilant for any signs of out-of-the-ordinary behavior.
Thanks, everyone!