My ***ed Up Family

tell me why my mother always talks about how im not suppose to talk shit about my family because its my family? lately she has been talking so much shit about my older sister and brother in law with my little brother. this past week i have been babysitting my sisters friends daughter and im not asking for alot of money because she is a single mom and she doesnt have alot. (my mom is a single mom too) this morning i was informed that i would be babysitting another little one tomorow. i personally dont have an issue with it. but my mother is getting pissed because i prolly wont get paid more money because i will be babysitting another child. then she proceeds to talk bout how my sister is "complaing" about how her and her husband dont have alot of money. when she doesnt complain. right now my mother is being a fucking hypocrite cuz she is talking shit about my sister when she always tells me not to talk shit about family. but what i dont understand is why is she doin it when she spends most of our money on herself so we barely have food in our house....what do i do???