I am frustrated with my sister

I am crying. She live with my mother more like bothering rather than helping. She lives cost free even get living support. My mother doing household chores most of the part. She just sweep and mop (sometimes) floor on sunday. My mother even do her laundry. I do my own laundry, I clean the dishes everyday, I still clean the house occasionally. I clean my own room. And I still give my mother money for us to live. I heard she give my mother money (through my mother asked for some groceries) but money from her isnt enough for my mother's living (even for her own living). I am frustrated, if I leave the house (and I should to earn money), how my mother live just like a free maid for that one sister.