I have Crohn’s disease and my calprotectin, bloods and colonoscopy always come back normal yet when I have an MRI on small bowel they see ulcers and active inflammation. I too went 20 years undiagnosed, I’m on steroids at the min and waiting to go back on a biologic injection.
I have had a lot of problems over the years though… what was your outcome. I hope it wasn’t IBD xx