Flash Burnout by L.K. Madigan

Flash Burnout is a "teen angst" novel with many different issues.  First, the narrator, Blake, is a 16-year-old in his first serious relationship.  But he has a good friend, Marissa, from photography class.  As part of a photography assignment, Blake takes a picture of a passed-out homeless woman who turns out to be Marissa's drug-addicted mother.

Once Blake discovers this, he is hopelessly intertwined in Marissa's life, as they find her mother, send her to rehab, and struggle with her abandonment, while trying to keep a romantic relationship with another girl.  This is a heartfelt story about a boy in love, trying to make the right decisions, but failing -- as most teenagers do at least some of the time.  Blake's tumultuous feelings are genuine, and there is no happy ending here.  I think this book will speak to many teens who think being a teenager is easy for everyone but themselves.