Wa Alaikum Assalam. I'm sorry to hear that you're going through such a difficult time. First and foremost, I am not a religious scholar, but I can offer some general information that may be helpful.
In Islam, it is essential to take care of one's health, and deliberately depriving oneself of necessary sustenance, like food, to the extent of harming the body can be considered harmful and discouraged. Anorexia itself is a serious medical condition that requires proper medical attention and support. It is important to prioritize your health and well-being and seek professional help to address the eating disorder.
Chewing and spitting out food can be a part of disordered eating behavior and is not a healthy way to cope with food-related concerns. Engaging in this behavior may lead to physical and psychological consequences. It is essential to communicate your struggles with your parents and seek their support in getting the help you need.
I strongly encourage you to talk to a medical professional or a mental health specialist who has experience in treating eating disorders. They can provide appropriate guidance and create a treatment plan tailored to your specific needs.
Additionally, seeking guidance from a knowledgeable and understanding religious authority may also be helpful in addressing any spiritual concerns you may have.
Remember that recovery from an eating disorder is possible with the right support and treatment. Don't hesitate to reach out for help from those around you, and take the steps needed to prioritize your health and well-being.