if you are eating less than normal, this can cause you to loose weight.
you need a calorie count to see how much you are taking in.
also you need to avoid lactose
you could be having bowel mal absorption problems and not absorption your nutrients properly.
some patients who have gluten allergies or celiac spruce disorder can have nutrient malabsorption problems in their bowels.
these need to be checked for
let me know if you have questions.