Riding a bike should not 'cause' IBS, though sometimes exercise can move the motility along - but overall it is a good thing and can be helpful.
You may want to look into hypnotherapy regarding the anxiety issues - it can be quite helpful, especially when you are doing all the right things otherwise and still have problems. I had gallbladder issues too, so can relate. It can help with all aspects of symptoms. If you have any questions, let me know - happy to help.