Curious, your mom may be in denial about her own mental health. Mental health usually follows physical health, the exception are those people who are hopeful for the best outcome and in the meantime think, speak and act positively. Other folks, instead of admitting to it, they will do anything to deny it even if that means belittling and minimizing the feelings of others. That behavior somehow "proves" to them that they are mentally stronger.

I don't like what she's doing to you but I want to encourage you to have compassion on her because if she's in denial, you are so many steps ahead of her in admitting to your difficulties and seeking help. It would be so easy for bitterness to creep in because of how she treats you. Bitterness will take what you're feeling now to a whole other level. Accept the fact that she may never understand but get the help that you need by any means necesary. During the process of your therapy you'll learn how to express yourself to your mom in a way that will empower you and that will make her back off.