Ahfu was recovering pretty well, but yesterday his health unexpectedly and rapidly declined. He's in a lot of pain, can barely move, and is generally listless and distant. His incision looks fine, he's not running a fever, but he's... just not well at all. We didn't even know if he'd make it through the night. When I left for work today, I had this feeling it will be the last time I see him alive.
We're taking him to the vet today, and we'll see what they say.
Update 10:15am - The vet says the same things we saw: incision looks good, he has no fever, and he's lost no weight. But he's in obvious horrible pain. They think it may be his spine (?) but admit it's a guess based on his posture. He's being put under 24 hour observation. Status is unknown, but better than, "Yeah... call the morgue."
Side note: I had to call the vet and tell them he's afraid of metal bowls. Really, Ahfu's been afraid of them his whole life. We're not sure why. Maybe it's his reflection, or the sound they make, but when he was a puppy he would bark at them and back away from them. He refuses to eat from metal bowls. They put a note on his crate for me.