Apocalypse: the Zombie Queen Is My Girlfriend

Why did my girlfriend's temperament change drastically after some 'happiness'? Why did I awaken my superpower? Does it have anything to do with the 'happiness' of the two of them? She left a letter saying that the end of the world was coming! And the countdown to the end of the world has begun in 72 hours? My girlfriend gave me a huge deposit, and I want to use the money to build a fortress to defend against the zombie attacks of the apocalypse! I couldn't contact my girlfriend from that day on. When I saw her again, her identity made me... This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.