Hi and thanks for the query, You might need to have a thorough medical review from a doctor. Common causes lack of energy are improper diet with inadequate vitamins (poor vegetable and fruit intake), anemia and some chronic diseases like tumors. A complete blood count to know the actual hemoglobin is very helpful for causes of anemia if detected to be actively searched for. Tumors, systemic diseases, autoimmune diseases and metabolic diseases like diabetes could lead to low energy. Screening for diabetes mellitus could be helpful too. Depending on the clinical evaluation, specific blood tests and radiologic tests could be asked. Consulting your family physician for an initial clinical evaluation, screening for common above cited conditions and adopting a healthy vegetable/fruit rich diet could help. getting enough bed rest could be of utmost good. Thanks and hope this helps as I wish you the best of health. Kind regards. Bain LE, MD.