Trying to figure out how to bring up endometriosis to my doctor

Hi all, please forgive me if this post sounds completely ridiculous; I wouldn't know where else to put this, and I don't have anyone I can talk to around me that would understand where I'm coming from, as they don't know what endometriosis is.

I got diagnosed with pcos when I was 19 (I'm 21 now), and throughout the past 2 years I've had 2 transvaginal ultrasounds. The first one was to check for ovarian cysts because I was on the combined pill at the time, and I was experiencing unbearable pelvic pain (which I still don't have an explanation for, as it wasn't cysts, and when I stopped the pill, it pretty much went away completely).

The second ultrasound I had was because I hadn't had a period in almost 2 years, and my doctor had given me progesterone to induce one, and apparently it was to check the thickness of my endometrium (thankfully it was normal).

I expected some pain during the first ultrasound because I'm a virgin, but on both occasions I experienced a lot of pain the entire time, and when I mentioned it to my doctor recently when she received the results of the second one, she suggested that I could potentially have endometriosis. For some reason, I have no idea why, at the time I said to her that I wasn't experiencing any pain or anything that would indicate that it was interfering with my life in any way. I don't know why I said that, because it was a complete lie, and as I've been at home and thought more about it and actually paid attention to the pain I get both (e.g. pelvic and lower back pain, heavy periods that last about 2 weeks that I get a lot of aching from, sharp pain when I feel my bowels fill up, struggles with urination, etc), I don't think dismissing it was a good decision.

My problem is that I really don't know how to bring this up at my appointment next week without seeming like I've just changed my mind for the sake of it, or I'm looking for attention, or I'm trying to get diagnosed with something I don't have. The last thing I want to do is waste people's time on me for no good reason. For all I know, I could be completely wrong, and what I'm feeling is normal, and I'm overreacting. I have no idea if it's even worth bringing up.

Any advice would be appreciated.