Endometriosis symptoms? Help please!!

So my whole life I’ve had normal, painless periods. About 6 months ago, out of nowhere one day, I got awful pelvic pain and it has not gone away. It changes a bit throughout my cycle but never goes away. The only time it becomes bearable is during my period (weird, right?). Otherwise my periods are still normal (every 27 days, lasting 4-5 days) and are moderate to light. Never leak through a pad or tampon. No issues using the bathroom. But the pain gets so bad sometimes I feel like I can’t breathe and I end up doubled over in tears.

About a month after this started I told my GYN and he basically laughed at me but still offered a transvaginal (internal) ultrasound. It came back completely normal. I plan to make another appointment soon because I just can’t handle this. I also desperately want children someday and the thought of not being able to gives me so much anxiety.

For those who are well versed in endo, could this be endometriosis? Or something else? Anyone have awful pain throughout their whole cycle with no other symptoms?

Thank you!