Goodbye, little friend
As I said, Tessa ate last night and even followed me eagerly when I gave them their night-time treat. She seemed to be getting better, and I'm sure I heard her eating this morning. But she was very lethargic and sleepy, and around midday I found her in her bed, gasping for air. I rushed her off to the vet straight away, but they said that her glucose was through the roof (it was borderline yesterday), her kidneys had failed, and that she had had a "neurological event", which I assume is a stroke. They put her on oxygen and a drip, but it was pretty obvious there wasn't any hope. So I called Greg and waited with Tessa, talking to her and stroking her, though she only seemed to recognise me intermittently, till he arrived, and we both said goodbye.
RIP, little soul.