It's crazy, of course, to hope that drinking a potion at random will change you back to your old self, but...could it be any worse than remaining a cat-girl for the rest of your life? (Well, actually, it could be a lot worse, but you're not thinking very clearly at the moment.) You stare at the mirror, fingers crossed, hoping to see yourself become male again.
What happens is entirely different. Rather than becoming a human male's face, yours pushes out into something more like a cat's muzzle, becoming covered in the same black fur that covers your ears and tail. Before you know it, the fur has spread all over your body. Your hands have changed; though they're still clearly hands, the fingernails have become retractable claws, and pads of thick black skin have formed on the palms and the bottoms of the fingers. Your feet have changed even more; they're now fully cat's paws, forcing you into a digitigrade stance. Staring at the mirror, you find that you've gone from anime-style cat-girl to anthropomorphic female cat.
Well, that definitely wasn't what you had in mind.