There's no reason why she has to know what goes on between you and your psychologist, if you'd rather keep it private. However since you seem to want your mother to understand your condition better than you should ask your psychologist to explain things to her.
Also, have you considered walking with your family somewhere quiet and secluded? Walking can be pleasurable and a great way to lessen stress and anxiety. While I understand that public walking can be scary there are always isolated spots where you could walk in comfort and you might even enjoy it.