Dearest Katie, please don't feel bad, no-one will be judging you here, and we all can empathize with your awful situation,nobody wants their home to smell like a cat toilet.

I had a few issues for only a small time when i first took in the girls, and it nearly drove me up the wall, and it was nothing compared to what you describe, i certainly don't blame you one little bit, I think you do indeed have to re-home her for the sake of your sanity, (your asset your home) and your other kitties too.

Maybe the medication Medusa suggested might work, and i know you will give it your best shot,I think you probably have done that already,I can only wish you all the best of luck with trying that or re-homing Suzie.