Your parents are breaking the law for not providing medical treatment for your depression and eating disorder. Please call childrens services or whatever county agency deals with abuse and neglect of children.
Dealing with these two health crises would be difficult for adults in the best of circumstances, but you are young and also being persecuted for your beliefs by the very people who are supposed to care for you. Please don't try to handle this alone. At least see your family doctor, and let him/her know what's going on.