Why I stopped reading the book

Recently, I've been reading the book "Everything I never told you", but I decided to stop reading after I read 20% of its contents. The story was about a high school girl who was found in the lake and her family members try to figure out the reason of her death. It was interesting story, but I felt something negative while reading it. That's why I stoped reading the book. Instead, I restarted reading the book "Project Hail Mary".