Did you know there are animal neurologists? Well, there are. And at the recommendation of our regular vet we took Gus to see a great one. When he first walked in the room he said Gus was very cute, and then a few minutes later said Gus was "so handsome!" so obviously he's a very observant and brilliant vet. (btw, that's not the only reason I liked him, but it certainly didn't hurt.)
Sadly, seizure due to tumor has been ruled back in as a possibility, but the neurologist thinks that because Gus seems pretty happy, it's more likely that he has a harmless movement disorder. (my mind went blank when the words seizure and tumor were mentioned so I can't remember what the movement disorder was called. but it's not uncommon, and is no big deal.)
He recommended an MRI to be sure- if it's a tumor it's best to catch it early- so we're taking Gus back in for one tomorrow morning.
Thank you all so much for your kind words and thoughts earlier today. Reading them as we sat in the waiting room waiting for them to tell us what was up helped so much.
Hopefully, we'll get a good diagnosis (movement disorder!) tomorrow and I can get back to posting about pretty, funny and yummy things.