Hi there ~
Having a bowel movement after eating, loose stools and pain in the rib cage
along with feeling nauseous are not associated with having symptoms of IBS
. You are probably having symptoms of a lower GI infection. I hope you visit with a gastrointestinal specialist to find out if you really do have IBS. It is not an easy thing to treat and you might need a psychiatric consultation as well as stress
are related to IBS as well. So cross your fingers and hope for an easily treatable condition.
I hope this helps.
Take care and have a lovely day!