Hello,ashleyelalonde, Left sided lower abdominal pain along with what appears to be non- formed stool (Diarrhea) does require further investigations. It looks like the symptoms started rather sudden and the duration is also short. Presence of mucus in the stool might suggest Irritable Bowel Syndrome or IBS for short. This is caused by sensitivity to contractions in the colon and also to distension of the bowel. At least you don t mention seeing blood mixed with the stool. That is a good sign although your stool has to be tested for hidden blood. Pockets in the colon or Diverticulosis is also quite common after certain age. If one of these pockets get inflamed then the condition is Diverticulitis . This may be mild, moderate or severe.This is usually associated with fever, chills and also diarrhea and sometimes bleeding as well. A CT-scan would be very helpful before you have colonoscopy. Early Colitis , inflammation of the lining of the colon such as ulcerative colitis or Crohn s colitis should also be considered. Hope this will be helpful to you and you should discuss more with your docto. Wish you well,