I remember reading it 5+ years ago. It was a series of one-shot psychological horror stories. I only remember one chapter of it: The main character finds out that her boyfriend is cheating on her with another girl. She stalks both of them and tries to kill them. She meets her "boyfriend's" future child and she (The MC) she's the one that ends up getting killed. We find out that the child killed her so that they can stop disrupting therre parents relationship. When the MC is about to die she realizes that she was delusional and actually wasn't dating the guy.