I used to experience the same problems with D. I followed Heather's diet strictly and took my Immodium daily. But whenever something very stressful came up, or I felt anxious, I would get an uncomfortable BM if not D.
It couldn't hurt to discuss the possibility of going on an AD with your doctor, especially if you are following the diet and notice that stressful situations cause the D. Personally, an AD is essential to me living a normal life. After starting Effexor XR, my IBS virtually disappeared. You still have to follow the diet religiously, though, along with exercise, etc.
Let me know if you have any other questions. I'd be glad to share my experiences