tripod kitty suddenly falling/walking different?

I have a cat who is almost 4.5 yrs old. She was found and rescued with her litter mates at a very young age, estimated to be about 3 days old then. Unfortunately this particular cat had gotten very injured, she lost her tail completely (it was found laying on the ground near her) and had to have one of her rear legs amputated as well. I adopted her as soon as she was old enough and she has been doing wonderfully...gets around great and can run and even jump fairly well. She always holds her leg stump up under her belly and literally looks like a bunny hopping as she runs. Last night I noticed she was suddenly holding her stump straight up in the air, really high like doing a sideways splits, which was making her lose her balance a lot. Holding it that high is also making her sometimes start spinning her rear around in a circle as she is falling backwards, she just spins a few times until she falls....she can still walk, don't get me wrong, but it is looking very difficult compared to how she has walked for the last 4.5 yrs. She's even trying to hold it up ridiculously high as she eats which looks really weird.

I was unable to get her to a vet today, I work long shifts and calling out is too much of a risk if I want to keep my job. I plan to get her to one as soon as I can, but since she doesn't seem to be in any pain I am praying it's not an emergency. Has anybody ever heard of a tripod cat suddenly walking funny and falling after being fine for years?

I wouldn't rule out her being in pain. This being a new issue after 4.5 yrs is quite concerning. I wonder if her hip is dislocated?

I encourage you to get her to the vet sooner rather than later. If there is a neurologic or orthopedic issue there can be consequences for waiting too long.

Thank you for your suggestions!

Yes I am getting her into a vet as quickly as I can but unfortunately I cannot compromise my job (bad time right now at my employment for many reasons). She is my baby, but it won't do either of us any good if I get written up for a missed shift without 48 hrs notice.

The reason I say no apparent pain is she is walking, jumping, chasing our puppy, and playing with her toys as normal. She is also just as cuddly as ever and when I rub her hip and stump I don't feel anything out of sorts nor does she give any noticeable reaction. Obviously this is not a 100% guarantee of no pain as animals can be deceiving, but I feel confident enough in that assessment that I am hoping I don't need to pay astronomical prices for an after hours vet right now.

I don't think the hip is out of joint or anything like that since it feels normal when I rub it and  move her stump. She is also not walking like this all of the time....she will take a couple of her normal steps with her stump tucked under, then suddenly raise it up super high and stumble or fall. It just looks really odd, like she suddenly forgot how to walk on 3 legs.

Could she have an inner ear infection?  it would throw her balance off and she may be trying to compensate w/the stump.  still a vet visit.  Is there someone who can take her in for you?

I took her the other day, although literally that same morning she was already starting to get better. Anyways, it was a vestibular disorder and had nothing really to do with her amputation besides the fact that she just looked extra funky because she was flailing it around, lol. She was otherwise perfectly healthy though, and since she was already on the mend there was nothing else really to do. By the next morning after that she was completely back to normal. All in all the dizziness only lasted about 2.5 days it seemed.

Thanks for the suggestions!