Saved By The Apocalypse

Unexplained mutations in the DNA are causing people to rise from the dead, coming back ridiculously strong compared to when they were alive. Some who arise are known commonly as ghouls, man-eating frenzied creatures that'll do anything to kill, the rest (the lucky few) become what are commonly known as zombies. These people however are still in control of their humanity and are holding on to fight the mutation. The story follows the perspective of a 16 year old boy called Sean Walker, a reddit mod struggling to make his way though life with what little money his family left to him, using working out as an escape from reality and in hopes of a better future for himself