I am concerned about her not being able to use her back legs. This can occur with
heart disease, when a clot is thrown into circulation
and causes a thromboembolism. The clot becomes lodged in the distal aorta and iliac arteries which leads to the legs, the circulation to the legs is either partially or totally eliminated and it leads to paralysis. It is a very painful condition. The pain itself can eliminate your cat's appetite.