Lower abd cramping

I have been having terrible cramps in the lowest part of abd.  Right above my pelvic bone.  I also have lower back pain when this occurs.  I had my gallbladder removed 7 months ago.  My bowel movements have not been the same since.  I have had periods of loose stools especially after eating certain foods like eggs.  I start having this cramping a couple hours after I eat and it lasts for up to  4hrs.  I still feel hungy.    My bowels are moving during this time.  They are soft and formed.  What is wrong?  Do I have irritable bowel syndrome?  All my doctor has told me so far is to take a fiber laxative which I do sometimes but this still happens.  I am not going to be able to eat certain foods anymore?  Help.