(O.k., it's month 4 now, but I did read the book in month 3.)
Yaqui Delgado Wants to Beat Your Ass, by Meg Medina (2013) was the "serious issues" book I chose (it came highly recommended), the issue in this case being bullying. When the main character, Piddy, moves, she finds herself at the top of a bully's hit list at her new school, even though she's never actually met the bully, the Yaqui of the title.
Unlike some other things I've read on the topic in recent years (including some supposed nonfiction), this book faces the hard truth: the only way to survive a bully is to stay off of the bully's radar (which is never completely possible). Grownups won't help, would be powerless if they tried, and telling would probably just make the bullying worse. It used to be that you could get away by making it to the end of high school and then moving out of town, but that was before the internet.
On a more pleasant note, the author does a great job of communicating a sense of place and atmosphere, and there are some realistically portrayed, strong, female characters.