What could cause someone to have diarrhea more often than not, and when it is more solid there's a gummy like substance to it?

Many possibilities: Irritable bowel syndrome is the most common cause of such symptoms. However, there are other possibilities as well, including inflammatory bowel disease (Crohn's disease or ulcerative colitis), bacterial overgrowth, celiac disease and other malabsorption disorders, and others. See your doctor and/or request referral to a gastorenterologist. Good luck!