I have been suffering from diarrhea for the past 3 months - with cramping in my abdominal region. thyroid test is normal. allergy tests - negative?

Various causes: Abdominal cramping and diarrhea in a 47 year old male raises concern for milk lactose intolerance, irritable bowel syndrome, and clostridium difficile infection. Of course an intestinal lumenal mass is to be considered. Medical and gastroenterological evaluations are necessary to provide proper differential diagnosis.

Many causes: Have you been traveling to a third-world country recently? If so , need to check for parasites. Have you been treated with a broad-spectrum antibiotic recently? If so need to check for c difficile infection. Do you have trouble only after consuming dairy products? This may be from lactose intolerance. See a GI doctor