Hi there and welcome to the forum. The mere fact you are restricting food so drastically and don't want to eat does suggest an eating disorder, quite possibly anorexia. Anorexia does not have to involve excessive exercise. I was diagnosed with anorexia almost 6 years ago now and exercise has never been part of my 'behaviours', but I was still admitted to hospital twice due to supposedly life threatening low weight.
My weight is now not classifed as anorexic so I feel bad and like I've failed, but my head is still ruled by anorexic thoughts so I am told I still have a diagnosis of anorexia because the illness goes beyond the physical state, although of course weight loss often forms part of it.
If you are eating so little, and I have restricted to that extent in the past, I suspect you will be losing a lot of weight and if you are not at an anorexic weight now you will be soon.
Do you have anyone you can talk to or seek help from? Believe me I know how hard it is to eat when it is the last thing you want to do because anorexia is not really about food or weight, but if weight loss becomes so severe that others start to notice and become concerns then control over what you eat can be taken out of your hands. I don't mean to scare you, but I have been through it and know it can be almost impossible to get off the weight loss treadmill once on it.
Do you see yourself as underweight? Have others commented on your weight? Why do you think you are not allowing yourself to eat more than 100 calories a day?
There is some more information on anorexia
here
Karen