I am going to re-name your thread and ask that each time you have a question about a fiber supplement, please keep it under this one particular thread entitled "Question about fiber supplements." It is difficult to keep track of your questions otherwise and you might get more responses this way. Also, members would be able to help you more effectively if you gave us a little more background information and let us know what you've tried already. Thanks for understanding.
You have to start very slow with fiber supplements or they will cause you worse symptoms than you are experiencing already. Methylcellulose, like Citrucel, might be a good bet for you, but again - start slow!