What Causes Fatigue, Diarrhea And Abdominal Pain While Having GERD And Anxiety?

I have been diagnosed with GERD, Generalized Anxiety Disorder, and I have been living without a gallbladder for over two years now. For a little over a year I have been experiencing episodes of fatigue, diarrhea/constipation, weakness, nausea, and abdominal pain in the middle and lower regions. What could be causing these episodes?