Everyone gave you such great advice! If you can drink peppermint tea, definitely go for some of that. It is great for pain.
One of the only things that concerned me is have you had any bloodwork done in your testing? That was the only thing I could see. I'm sure Heather will have some input on that.
If it is IBS, you definitely want to try Breaking the Cycle . And, remember this is just for a few days to get you stable. After breaking the cycle, please follow Michelle's advice and do not eliminate insoluble fiber from your diet - please just eat it carefully (cooked, pureed, chopped, etc.). Many people become afraid of insoluble fiber, but it is crucial for good health.
Glad to see you have Heather's book. Keep reading and trying things out, and let us know if you have any questions.