The main issue as described is Chronic anaemia
inspite of a good nutritious diet. The common causes under the circumstances are Worm infestation, Haemoglobinopathies, aplastic anaemia, leukemia
. The solution demands a good clinical examination (esp. liver / spleen
enlargement, lymph nodes, bone tenderness), a complete Blood Count
, Peripheral blood smear, Stool examination and review after the result of the above tests. If these tests have already been done, their reports may be communicated for further opinion.