Mary, I did not have your particular issue, but you can read about mine if you click on my link in the moderator's reply to you. I had taken at least 3 different antibiotics in rotation and it was not helping my IBS issues at all. I finally got an appointment with an excellent GI doctor's P.A. and long story short, she put me on 30 days of Xifaxan for small intestinal bacteria overgrowth, and that worked. I do follow a pretty strict diet. I think you need the best GI doctor you can find in your area. You are so young. You want to get this condition cleared up if at all possible. Amanda, the moderator, has given you some excellent links from the Mayo Clinic. I wish you the very best.