Fearless: A Survivor's Account of the Zombie Apocalypse

After a vaccine meant to protect against a biological weapon backfires and turns those who are inoculated with it into zombies, a young woman, having survived the initial outbreak, now runs with a group of others who stick together for safety, not that it does them much good. When she picks up a notebook in a grocery store her group is looting, she decides to begin a journal for future generations (if there are any).