Hi Jane - I'm currently going through exactly this with Charlie, he became ill very quickly on Sunday, he was on his own for half an hour, then we found him lying on the floor all twisted up. He's being treated with antibiotics, panacur and steroids (initially but not any more), and has been with the vet since Sunday. He seems happy enough, he's eating and wants fuss/snuggles, and has shown a slight improvement physically. He's no longer twisted up but is still lying on his side, yesterday he started to lift his head up and today he's definitely trying to sit up and is moving his head round more.
Does it sound more like an ear infection or EC? From what you've said we shoudl probably have seen more improvement if it was an ear infection?
Also, what is Stemicil for?
Spacegirl - my thoughts are with you, its so heart breaking seeing you bun poorly, I hope Gismo gets better soon.