What's the Name of That Book??? discussion

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Before, After, and Somebody In Between
SOLVED: Children's/YA
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SOLVED. This novel I am trying to find is about a girl who deals with the challenges of a mother who is a drug addict and has to live with another family for a majority of the book. She also plays the cello. [s]
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Also, I remember most of the plot which is why it drives me crazy that I can not find this book.
Here is what I can remember...
The main character is a girl, and I wanna say fourteen. Her mom is a hardcore drug addict, her father was put in prison (cant remember if the reason was given or not in book) and was killed by another innate via knife. She played the cello (i believe, am not 100 percent sure) and was able to afford it by stealing money from her neighbor’s brother (the neighbor is a kid her age and they were friends).
She eventually was taken in by this rich family (the daughter was mean to her from what i remember and was also into the party scene). I want to say the MC’s name is Martha. The daughter of the rich family wanted to call her something else and asked for her middle name, she told her it was Georgina, and the daughter shortened it to Gina. She also started dating a seventeen year old pianist at one point. He broke up with her after finding out her real age though. One of her friends from her mom’s neighborhood had a sick mom who eventually dies in the book and by that point she basically loses her friends because she likes where she is now/changed.
Towards the end of the book the mom gets Gina back and she has a boyfriend from rehab. She relapses eventually though and the boyfriend leaves all the while Gina begs him not too cuz he was a pretty decent guy. Gina then sees her neighbor in town only to see that he has ended up just like his brother - who was involved in criminal activities. She is distraught over this and goes to call the dad from the rich family. He calls her Gina and she corrects him by saying “My name is Martha”.
If anyone can help me find this book I will appreciate it.