If you're purposely under-eating - which you are - then you have an eating disorder. Congrats! If you feel hungry throughout the day and could eat if you wanted to, then your problem is mental and you should consult a specialised counsellor. If you're not hungry and couldn't stomach any more food that you're currently consuming, it could be physical and you should consult a medical physician.
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The woods are lovely, dark and deep; But I have promises to keep,
And miles to go before I sleep - Robert Frost