IBS is a diagnosis of exclusion.
IUC/CROHNS DZ/IBD is inflammation
usually DX by BX IBS SX can be managed .You need a full exam and blood work. Especially screen for H pylori . Also stool screen x 3 for occult blood
While you are getting these items checked out you should stick to a gluten free diet
. Ie gutbliss.com and Wholeapproach.com The SX wax and wane.