Irritable bowl syndrome. Frequently.

Hello doctor I have been suffering from an intestinal infection since 3 years now it's not going away. I had a CT scan in which it showed mucosal fold thickening in jejunal an ileal loop and 9 mm mesentric lymph nodes non specific jejunoilitis...i had my ers also increased that is 53 after the course of antibiotics my esr became normal with rifagut and econorm but again it started happening since a week....... I started having econorm my stool became better than before...but why is it happening again and again and I am unable to gain weight doctors say it's ibs but it should be fine by now... I m afraid of my weight it's only 38 and not increasing what if things get complicated...also I experience mouth ulcers frequently.