I don't know if I asked you this before but.....have you tried going on a gluten free plan for a couple months to see if this helps. Many who have IBS are actually gluten sensitive and when they cut it out they feel better. White starchy foods get digested too quickly which is why your blood sugar goes high. One of the ladies on the show called The View has gluten intolerance and she has a good cookbook out - I forget her name.

Have you tried adding Aloe Vera gel - you can drink this and most like to mix it with half juice -this is soothing for the intenstines. Also heard Siberian Ginseng is good for blood sugar. Gravol makes a natural Ginger pills which soothe nausea but is also good for stomach upset. I would love to see you try a completely gluten free diet and see how you react to this.