I was the same way as you, except I had constant diarhhea for over 18 years. I have had all the testing done and come up empty handed....I decided that this was just how I was going to be the rest of my life.
I went to a new Doc in January, who I really HATE!!!! He listened to me and listened to my symptoms, called me a liar and sent me on my way with a prescription for Cholestyramine. It is a powder that you take once or twice a day mixed with water or juice....I have to do orange juice cause otherwise it is kinda nasty tasting. But, I have been taking it since March 18th and I have not had one episode of Diarhhea at all. I have never gone 12 days without D. I usually go 1-10 times a day everyday and it was always diarrhea.....
I now have formed regular BM's.
It might be worth a try for you. It sure gave me back my life after 18 years!!!