Hi,
Welcome to the forum. I am really glad to help you out. You do seem to suffer from an eating disorder and for the same you need to consult a psychiatrist.
This disorder is called anorexia nervosa, when a person eats too little to sustain oneself and this can result in a marked thinning of the body.
There's another disorder called bulimia nervosa in which a person tends to go in for induced vomitings to throw out everything one has eaten and it is usually due to the fear of weight gain and the associated guilt.
A psychiatrist or a clinical psychologist will be the right person to help you in the same. I sincerely hope that helps. Take care.