Good evening,
I'm really glad to be able to share my experience with you, as it's actually quite a reassuring one.
Today marks four months since Etoile's amputation, and she's doing really, really well. Her life now is pretty much the same as it was before the op, except that she goes outside for shorter periods and I think she ventures a bit less far. She does seem to tire more quickly after her outdoor outings. So, broadly speaking, she's become a little more of a homebody, but otherwise she's genuinely doing great.
Over the weeks she's made real progress. At first her ability to jump up to higher spots was limited — she could get onto the beds, the sofa, and the chairs, but she couldn't manage the windowsills or the table anymore... but over the past few weeks she's been able to do that again!
Similarly, she's recently started absolutely loving her cat tree. She has these mad moments where she shoots up it at full speed.
And what's been wonderful for me is that our other cat (they're from the same litter) eventually accepted her again after about 8–10 days, and they've got their old bond back. They're chasing each other round the garden again (when Etoile runs at full pelt, you'd never guess she's missing a back leg — the speed she gets up to is remarkable). I think her sister could smell the clinical odours on Etoile when she came home from the vet, and that's what caused the rejection in those first few days.
One thing worth noting is that the vet had recommended keeping her indoors for around a month, but as she seemed low in herself, I didn't wait that long. I let her outside under my supervision before the end of the first week... at first I'd bring her back in fairly quickly, and gradually I eased off and let her get on with things in the garden herself.
Personally, I felt that letting her get some fresh air really lifted her spirits — she loved scratching at the ground, nibbling the grass on the lawn, sniffing around, chasing insects :-)
PS: As she's more vulnerable now, I make sure she no longer goes out at night.
That's my experience, for what it's worth.
I truly hope your cat also finds his or her confidence again and gets back to enjoying life as a cat, even with this challenge. I completely understand how you're feeling. It was very hard for me to see her like that at the beginning.