What Causes Fatigue, Abdominal Pain And Mucus In Stool?

Hi, I ve been having some problems and I just wanted a professional opinion. What could all of this mean? Symptoms: Fatigue, abdominal pain that varies in location by the day, bloating, mucus in stool, extreme loss of appetite and nausea, weird kind of polyp-ish type things on/in anus that sting when I use the restroom, just feeling generally crappy... I m 19 if that helps at all. Thanks for your help!