How did you know you had endometriosis?

Hi, I'm 28 and just recently got referred out for surgery for suspected endometriosis. I'm nervous for a multitude of reasons (one being that the surgeon I was referred to seems to have a lot of bad reviews) and I keep second guessing my symptoms and thinking what if I don't have endo?

I've had severe period pain since I was 12 along with irregular spotting and even breakthrough bleeding while on the pill and random nausea. I have severe lower back pain and deep sharp hip pain that comes and goes, all of these symptoms have been more consistent and occur even with suppressing my periods. I've also had a bone deep exhaustion that seems to be constant and brain fog that has been constant for the past three years. I've been to the GI due to having random bouts of of diarrhea and had an endoscopy and colonoscopy performed to which I was told nothing was found. There were x-rays taken prior and my GI told me I was impressively constipated and that maybe that's causing the pain. I've also been told it could be fibromyalgia or that I'm hypermobile and I'm just overextending myself.

When I look up my symptoms they all lead to endo, every symptom that google seems to have listed is what I experience but I'm still second guessing myself and I'm also scared that either the pain will be worse, something will go wrong or they won't find anything.

I guess what I'm asking is how did you know you had endo or how did you decide to look for answers.