I absolutely agree with FurballsMom, go see a naturopath! I went to my doctor and she told me to take some Benefibre and sent me on my why. Not helpful. Then i went to a naturopth and we tried trial and elimination diet but that doesn't always work, heres why: Most people with IBS have mild allergic reactions to a certain food, however they do not get symptoms minutes after they eat it (like someone with an allergy to peanuts would) but would get it hours or days after! So pain could come at anytime, even after you eat something you are not allergic to. And thats why my naturopath recommended a blood test - I found out I was allergic to dairy! More specifically the proteins in dairy (whey and casein). I cut dairy out of my diet and now feel absolutely fine!!!!!!! I felt like you a year ago - that food was my enemy, but it doesn't have to be that way! :)
I would recommend you see your doctor about this. In the mean time, I would recommend you try eliminating 100% of all lactose (milk, cheese, butter, ice cream, yogurt, etc.) for 2 weeks and see if that helps.
You could try seeing a naturopath. You don't have to stop seeing your regular doctor. A good naturopath will not suggest this at all. A naturopath could help you with a trial elimination diet.
If that doesn't work there is something else that I've heard talked about in complimentary medicine, but right now I can't think of the exact terminology for it. It's very different and involves a hospital stay if you try it.
So, you could ask your question in complimentary medicine. One of the regulars or team leaders will speak up about this and give you the correct terminology.