I"M  LOSING MY FUCKING MIND. Okay so, I read this book a few months ago and it was amazing and I can remember the plot clear as day but I can't remember the title, author or the names of the characters. I've been googling for the past hour and I CAN"T TAKE IT. If any of you know please comment and tell me I beg of you:

This girl changed her name and wen tot a different high school. There, she met this 'pretty' popularish girl and they became friends. They partyed with the girl's older guy friend. This guy friend is in love with the popular girl but she can't tell (even though they have sex and kiss and all that). They go to a beach house and the popularish girl takes her top off and goes skinny dipping and the girl who changed her name just goes along with the ride.
   The reason the girl changed her name is because her little sister and her were kidnapped and the little sister was raped after they left a party. The girl left her boyfriend and best friend at the party to take her drunk little sister home so they hitched a ride with these college guys. It turned out, however, that one of the college guys was the popular girl's brother and the girl is secretly after revenge.
   "Along the way, the girl who changed her name met this other girl friend and the girl friend  introduced her to her younger brother who is a drummer in his band. They fall in love and she eventually gets pregnant and I think they get engaged. But, on one of their dates, the popular girl finds them and pretends to be her best friend again but goes crazy. She runs out into the ocean and drummer boy ran out to save her. They both died\drown.