i dont know what to do, my heart has broken,

miley started losing the use of her back legs 2 weeks ago, she has practically lived in the vets over the past two weeks, we are shoving anti-biotics down her throat, shes not getting any better, she had an x-ray yesterday which shows nothing, she has had blood tests which show nothing, she threw up 4 times today and is staying at the vets all day under observation, no-one knows whats wrong with my baby. i cant take it anymore, her little face is permantly sad, what do i do? anyone else know of any other kitten which has done this? shes only 6 months old. bless her x x x

thanks for listening :-)