I've been feeling more tired and have some abdominal skin itching. when should i see the doctor?

May be a virus: Being tired, and also having an itch, may be two unrelated problems, or they can be caused by one disease. A virus may make you tired and also give you itching, so can a more serious problem like a lymphoma. An allergy to a medicine or some other allergy may do this as well. If you' re really tired, can't even get out of bed, and have itching, and it lasts more than a week you need to get help.