that happened to one of my cats when she was only 2 years old. The emergency vet
thought she had broken
, but couldn't find any fractures (this was in the middle of the night over the weekend), the next morning, when she lost functioning of two more legs, she had to be put to sleep. It still makes me cry just thinking about it...
I really hope this is not the case with your cat, but I definitely wouldn't take any chances. If you haven't already, please take her to the vet ASAP!