Unfortunately, as a child, there’s very little that you can do. But, that doesn’t mean that this kind of behavior should continue. Please find an adult that you trust, even someone in your extended family to confide in. Make sure they’re ‘getting it’, and this adult should be someone you trust and someone responsible enough that this shouldn’t backfire on you or hurt you in any way.
Please, please keep in mind, that no matter what mom does, it’s about her, not about you. So don’t beat yourself up that maybe there’s reason for this or maybe you did something wrong, and most important, YOU DO NOT DESERVE THIS. Good Luck.