Basically, Jake got ditched by Drew and got kicked out of the music club, and then he met the Showrunners.
After hanging out with the Showrunners for a while, they reveal that they were the victims he used to bully and actually wanted him to become an outcast like them and ruin his life.
After realizing that nobody cared about him, he locked himself in his room.
Only his sister Rose knows what happened to him, but she won’t tell a soul...