Need help about my parents

I totally just need to rant for a little bit. My parent's marriage is falling apart and they will probably get divorced. My mom left and keeps thinking she can just come and go as she pleases and my dad has to take care of us. I have some issues with depression and my mom is the only one who really gets me but she's not here for me anymore and I can't take this. She just walks all over my dad and he's the most depressed he's ever been and just lets her do whatever she wants. Does it make me a bad person to be mad at my mother? Any advice would be greatly appreciated.