Your GI is trying to check for signs of infection and probably seeing if your ALT/AST levels are elevated as this signals liver inflammation, a good place to start. Have your doctors told you that you test positive for gluten intolerence?
What exactly is your diet like? Are you getting enough natural fiber (25-30 grams) and water? Before you ask for drug that bind bile, have you asked your GI about
trying a fiber supplement such as Citrucel or Metamucil as this can help firm up the stool naturally? Another thing to try is yogurt as this has calcium and probiotics, also helpful to firm up stool. I like organic Stonyfield, but this is just my choice. Some people have had luck with taking calcium pills as well.
I had my gallbladder surgery 4 years ago and had the same bile diarrhea that many people go through. One thing that helped is to avoid fats, and certain foods that gave me problems, leafy salds, salad dressing, and spicy greasy things. I had problems digesting red meat, something I still avoid. Back then my GI gave me a script
for Welchol(cholestrymine) and it caused such bad constipation that i had developed aggravated hemmorhoids, wish I had tried the natural fiber and probiotics first!
Good luck and hope you feel better soon!