Another World's Zombie Apocalypse Is Not My Problem! (Light Novel)

Just when I thought navigating high school was bad enough, I woke up to a rotting, post- apocalyptic world! I thought that the poisonous swamp surrounding my small island would have protected me from all the drama, but what did I see staggering my way? A nasty, putrid zombie! With nothing left to lose, I shoved it away! To my surprise, it turned into a living, breathing, not- so-dead human! So, I have the power to purify zombies. And now I'm expected to save this undead world from the zombie apocalypse? Great. This is so NOT my problem!