Please help me know the name this story

He survive in a zombie world for years but then he died and travel back to time where the zombies is just about to be free(?) he then became a student again and save his boy bestfriend, they have like powers when they're like meditating, like that. And he's trying to find his like lover or gf. If i remember correctly the date of the start of zombie thing is Valentine's day, Feb 14 i think. And in chapters i always saw a pink haired girl in a police uniform