Lady Misfortune

Help! Looking for this book: A South Park story that has a male protagonist (I think he was male reader) who was friends with everyone and popular until a high school party where Wendy tried to flirt with him, and when he turned her down since she was dating Stan, she lied and told everyone he tried to r×pe her. Everyone hated the protagonist and bullied him relentlessly until he moved away. Then this story becomes a crossover with Invader Zim, and he cuts off everyone in South Park. Kyle exposes Wendy's lies about the attack and tries to get the protagonist to come back, but he refuses, saying Kyle only did that to alleviate his guilt for the bullying because even though he didn't participate directly, he ignored it going on. This may sound like a cliche story, but it's been on my mind since I've never finished reading it!