when anyone is upset or in an emotional state, the body will usually suspend the appetite, or any desire for food because its energies are channelled elsewhere. The same could be said while exercising, or immediately after exercise where the desire for food is usually suspended. Genuine grief at the loss of a loved one and undue stress are other examples.
Eating under these circumstances will only give rise to imperfect digestion if not chronic indigestion, and the fermentation/putrefaction of foods within the digestive tract adding to the burden of toxemia.
In my view I would go ahead with the fast as planned, as this is what your body is calling for.
Listening to the genuine needs and wants of your body is the greatest service you can do for it, and a disservice if you do not.