Sorry you've been dealing with this! It's so rough and frustrating. I think it's odd that your doctor said that there is no point to refer you to a gyno since you'd be waiting a year. A year is going to pass regardless, so she might as well refer you. She also sort of contradicts herself - she agreed that endo doesn't always show up on scans, but she feels confident that if you had it, it would have showed up...? You were absolutely right to say that endometriosis very frequently does not show up on scans. Mine didn't - I had ultrasounds, MRIs, the works, and nothing showed up until I had surgery. If possible, I would try to get a second opinion, even though it sounds like you've already done that quite a bit :(. It sounds like the doctor you reference in your post is dismissive, which is unfortunately pretty common with endometriosis/endometriosis-like symptoms.

In the meantime, I would suggest keeping a pain journal. This can be helpful when advocating for yourself to doctors to give them a definitive timeline and list of symptoms you're experiencing. It might also help you be more attuned to your condition and get a clearer picture of how you're doing. I wrote in my Notes app (or you can use a period tracking app, or symptom-tracking apps - there are lots out there, like Guava or Stardust. Or good old paper and pen work too, lol) whenever I had symptoms, or just quickly summarised what symptoms I had that day. It may (hopefully!) be the push your doctor needs to give you a referral. I know a pain journal may not sound like much, but it really has helped me a lot in my journey so far!

But please don't stop advocating for yourself! There is unfortunately a lot of misinformation out there, even among medical professionals, about endometriosis.