Sorry to hear you are having a rough time,
I went through the same trauma as you recently, all the tests, the frustration of doctors!!!
I have tried i dont know how many pills, fibredrinks that look like wallpaper paste, meditation...and so on. It was only in the last few weeks that i have started to feel really good and dont need to rush to the loo everyday. The reason being I eat healthier and take nutritional supplements! I have found this wonderful supplement which you mix as a drink, its not just for ibs, as i said its a nutritional supplement, i wanted to be healthier and i did suffer with acne so was hoping it would help my skin, I noticed the difference with my ibs after just a few days. you have to remember to take it everyday and also i did not know how long it would take before i noticed anything as everyone is different, but i feel so much better. Pills take a long time to absorb into your system and only a percentage of the contents actually go where they are needed. They may work but it is trial and error until you find one that works for you. I take a nutritional drink so its quicker. Its weird but i feel my 'insides' are healing, if that makes any sense?!. I really think good well balanced nutrition is the key. Try Reliv products, they have various ones, i use their classic which is all round nutrition and innergize which is an energy drink, i mix them together and drink.
Hope this helps.