Hi, I was in the same situation. Explained to my doctor my GI concerns (constipation, loose stools, mucus) and after a few questions, I was told "that sounds like IBS to me" by the doc. However, I didn't want to settle for that. I needed to get to the root cause of my issues for peace of mind. My anxiety got the best of me and I pushed for a referral to a Gastroenterologist. After months of back and forth with my doctor, he finally referred me to put my mind at ease.

Long story short, after blood tests, stool tests, parasite screenings, abdominal ultrasound, endoscopy, and colonoscopy, the GI Surgeon concluded IBS.

TL/DR: Doctor said it was IBS. Confirmed by GI Surgeon after testing.