Oh my god Snowball spent all night outside and my brother found her at 10 in the morning. She was dirty and limping a bit but it seems she's okay, her leg's not broken at least, though she seems a bit distant at the moment. She seems like she's a bit mad, I don't blame her. Poor Snowball.
EDIT: I finally saw her, the poor girl is really sad and she doesn't talk unless she wants you stop touching her, which was only really once surprisingly. Her meows when did that sounded weak but otherwise she seems fine for now, she's currently laying next to my mom in her room while she's reading the book I had to read for one of my classes. My mom thinks she sprained a muscle or something but she can walk at least if a bit slow of course. When I got home she slowly got up when she saw me.
Her fur is all matted and grey but she doesn't seem sick. I hope she'll feel better as time passes but we'll keep an eye on her.
EDIT 2: Seems like she's sleeping now, that's good.