Yes, you have found someone who had IBS for years before diagnosed with IBD. I still have problems keeping the symptoms straight at times.
Twice when having bouts of D I had a sigmoid and the doctor found nothing abnormal so still called it IBS. I think I heard IBS for the first time when I was about 35 or so but always seemed to have a "nervous" stomach as Christine said back in the 50s. The true difference that I have found for me is the bleeding and mucous. I NEVER had that before UC. BUT - my gastro doc thinks it is possible that I had UC a little sooner than age 67 (when diagnosed) but was in remission when I had the tests. Who knows? Anyway, what you eat affects IBS so much more than the UC for me! I always had IBS with D - never C. Another difference is where the gas is present. Now my gas with UC is in my rectum - with IBS - always burping and heatburn, etc. I take Prilosec and gasX for IBS and trying to eat lowfat/low spice and small amounts throughout the day.
ElaineNY