it's been a long time since September, so I guess you must have lost a considerable amount of weight. You definitely should see your GP and tell him about your symptoms. Eating disorder usually starts with changing the way you think. If you don't feel like having low self-esteem, feeling fat etc, it is probably not an eating disorder. However, if you cannot eat and throw up you will become seriously underweight no matter what's the cause. Seek professional help as soon as possible.
Also, your problems might be caused by some ingredient in your diet. Do you vomit after every food? You might have a food allergy, coeliac disease, or it might be "just" an infection.
It sounds like you have digestive problems like me. It doesn't sound like anorexia though, but I am not a medical professional. I would get some help from your primary care physician first before jumping to any conclusions about an eating disorder. My eating disorder first started from stomach pain and gallstones, and even helibacter pylori which is a bacteria in the stomach lining.
You should really consult a doctor before you end up like me. An eating disorder is not anything to play with and it will end up taking over your life. I would have a doctor to check for hbp, infections, maybe they can do some CBC to check your blood work for possible answers....usually after three days of discomfort though, because it could be a virus.
Robles