Got there about 6:45 or so, and the lady working the counter went out the back to pick him up, and when she did he seemed very jerky and twitchy. This worried her, so she called the other vet over to have a look at him. After another look at him, they brought him out the front and he was not himself. Very twitchy and weak.
After a bit of a discussion between us, it was decided that it would probably be best for him to stay there overnight for observation, and they put him on a drip.
The general consensus is that it's probably a toxic reaction to something. The drip should help his system flush whatever it is out, so he should be fine by tomorrow evening. I hope so.
(As an aside: One of the questions that the vet asked was wondering if there was anyway Spitz might have eaten some pot! :)
I give him a little bit of a cuddle and then go home. Xavier certainly noticed that something was wrong, as he was exceptionally affectionate and clingy. I had some plans for the evening, but I ended up scrapping them and spending the night in front of the TV with Xavier on my lap.