Your symptoms certainly sound like Irritable Bowel Syndrome. You did not mention whether or not you have had a colonoscopy and stool cultures performed. If not, then these should be done to rule-out other potential causes of frequent or loose stools. If you do, indeed, have Irritable Bowel Syndrome, then adding as much fiber to your diet as possible may be helpful (Citrucel or Benefiber are available here in the USA). Also, pay close attention to your diet, and try to avoid foods that make your symptoms worse (although you must still try and eat a healthy, balanced diet).
Although it is impossible to make a diagnosis or recommend specific treatments over the Internet, I hope that this information will be helpful to you.
Sincerely / Robert A. Wascher, MD, FACS