Me and the Gorgeous Teacher in the Apocalypse

Apocalypse Novels Are No Longer Popular, and There Aren't Any Good Ones Either. Debate Me

Awakening, Dungeons, and Stockpiling

Looking for a book: It starts with the female lead awakening in a high school classroom. She hears an announcement saying that some people will be sent into an instance in a few minutes. The first instance is post-apocalyptic, and she teams up with the campus heartthrob and the school bully. There's a scene where they stock up on a small amount of supplies.