sounds like it could be Crohn's
Colitis involves the colon, not the small intestine or the stomach. Have you thought of the idea of Crohn's disease ?
These are all symptoms of crohn's and other that stomach lesions UC has the same symptoms.
You could look into symptom management via medications. Probiotics and Metamucil help, as well a magnesium, potassium, curcumin, wobenzym, and boswellia.