The crossword solution for the term 'FEELS BLAH' is AILS, which is an acronym for 'Acute Infectious Lymphocytic Syndrome'. AILS is a medical condition that is characterized by a feeling of general malaise and fatigue. It is caused by a virus that affects the lymph nodes and can lead to a variety of symptoms, including fever, chills, muscle aches, and swollen lymph nodes. Treatment typically involves rest, fluids, and medications to reduce the symptoms.