Misdiagnosed with Endometriosis: Seeking Answers

Has anyone been told they have endometriosis before to then find out it’s something else? I’ve had painful periods, chronic pelvic pain and dyspareunia for many years, an 8cm endometrioma showed up on a scan which was due to be removed, but on a second scan it went away so never went for surgery. Yesterday I had diagnostic laparoscopic surgery for endometriosis/pelvic pain and they found no endometriosis at all! Doctor said it’s unlikely to be that as the cause of my pain and I had loaded bowels and inflammation so I should look down the digestive/IBS route. I have had constipation throughout my life but previously thought of it as a separate issue. Is there anything else it can be? I’m so so tired of the pain!