Why won't my mother belive that depression is a real disease?

Have a family session with your therapist. I'm glad you did go to see one, despite what your mother says. I have depression as well, and see a therapist. And think that some people don't believe it is a disease, or a real problem, because you can't really physically SEE the disease, like on an x-ray, or through a blood test. I hope you can get some medicine, which sometimes it's trial and error, on getting on the right one and dosage. Which also is another reason why I think people don't believe depression is real, since it's trial and error.