Well, we got back from the vet's about half an hour ago. Gizmo is freshly neutered and came through everything just fine. He seems a bit unsettled, pacing around the house, but not overly distressed. I'm assuming it's just the stress of the day (he's never been away from home before, poor baby) and he'll settle down in a while. He's also flipping between 'I want affection' and 'leave me alone, pesky human'. although I suppose that's not really that different from normal
Thanks for all you're advice on this matter, folks, I truly do appreciate it!