Suspected endo rant

I have suspected endometriosis. I've experienced pelvic pain/IBS since I was 8, and severely painful periods since I was around 12 (I'm now 23).

I'm sick of the pain and some of the nasty symptoms I'm experiencing (diarrhea, constipation, bloating, nausea, very weak bladder, pain during sex/when inserting a tampon, fatigue, chronic and localised pelvic pain, sometimes vomiting, but I have a strong stomach despite the bowel issues). However, I'm still waiting to be considered for keyhole surgery through the NHS.

I don't experience heavy bleeding as much as I did when I was a teenager, but I sometimes experience minimal bleeding during a period despite pain, suggesting retrograde menstruation? I also don't have much of an appetite when I'm inflamed, bloated, and having bowel issues, which I'm really struggling with at the moment.

The pain is just too much: it's constant, it's daily, and it's overwhelming. It's not always severe, but it's enough to make me cry. It's coming from so many areas of my body: all over my abdomen, my back, my ribs, my chest. I just feel so inflamed. I can't take many painkillers due to their side effects of constipation, which makes the pain even worse.

Despite all this, I'm still questioning whether I have it or not, and whether it's just stress and severe IBS. Everyone around me thinks it's endo. They didn't find it on ultrasound/MRI - only a 20mm cyst. Following this, I was discharged without being notified, so now I am waiting for my initial gynae appointment for about the 5th time to be considered for surgery. My local doctors are finally listening and believe that I have suspected endo, but gynaecologists in the past have not listened. I'm also scared as to how I'm going to live and cope if nothing at all is wrong.

Does anyone have any advice on how to improve symptoms? I already know not to consume too much sugar, alcohol, processed foods, coffee, etc. I also practice yoga, mindfulness, and I get enough sleep despite feeling constantly fatigued.