How do you switch guardianship. If your legal guardian/parent disagrees?

I am 17 years old. I have been living with a friend for the last month or so. My parents were completely fine with me staying here and then all of a sudden that changed. My mother was willing to sign emancipation papers, but come to find out. there is no longer an emancipation law in the state of pennsylvania. My household is very violent and children and youth services side with my parents on everything. My mom is an addict and I just want to finish school in a stable home. But, My mother has not financially supported me for the last 33 days. How do I go about getting guardianship changed if my legal guardian is not cooperative about it?