Surviving the Apocalypse: Being Stabbed in the Back by His Fiancée at the Beginning

Extreme temperature rise, roaring monsters, and broken homes. Where should we go tomorrow? Chen Fan struggled to survive in the apocalypse, but was stabbed to death in the back by his beloved fiancée! I thought I would die, but unexpectedly I returned to my twenties. When I return to this life, I must kill all my enemies and end this damn apocalypse!