What Is the Name of This Book? question

Ok so a couple of years ago i had this good supernatural fantasy? book in my library but i guess I lost it idk? Anyway i cant seem to remember at all the name and i would like some help. It is about a girl who can see ghosts and talk to them, her dead sister included, that always roams in her room and if I remember properly, constantly tries to live her lost life through her younger sister. I think she also used to live with her dad. She is pretty much an outcast in school, and only talks to the ghost of the boy who is tied to the school. There is also this group of popular kids who are always in the center of attention, the most popular one being a boy with a constant "oh I'm on the verge of bursting into tears, I am so pitiful and devastated after my mom's death" kind of look. Girls would always swarm around him with snacks, trying to cheer him up. Anyway, he finds out that the main character can see ghosts and begs her to help him talk to his dead mom, that is tied to the house and cannot leave Earth. The book has no romance in it, and it has a pretty gloomy and depressing mood throughout the whole read. These are all the details I could squeeze out of my head, hopefully it will help. Thank you!!