Could it still be endometriosis?

Today I had a disappointing appointment at a specialist: my uterus and ovaries looked good.

For starters, I'm from Finland, so I might not know all the correct English medical terms.

I got my endometriosis diagnosed in student healthcare (university). A doctor asked me a lot of questions, and tried to do a vaginal exam. She couldn't see enough, because it was very painful to me, but she still diagnosed me with endometriosis, due to the answers I gave.

I have very bad pelvic pain, bad period cramps, and lately it's gotten so much worse. It's sharp pain that radiates from my uterus to my hips, back and even down to my knees. Period flow and cycle are normal. One odd symptom that I've had is the need to pee. Peeing doesn't hurt, but I have to pee so often, because if I don't, I get horrible cramps. I feel like my uterus might be putting pressure on my bladder, if that's even possible. Normal life quality has suffered from the amount of pain I am in all the time, and painkillers do nothing.

Today I saw a specialist that the student healthcare doctor assigned to me, and she examined my insides and did a transvaginal ultrasound. She said that both my uterus and my ovaries looked fine, and that she couldn't find any endometriosis. The prosecute was very painful to me, as I feel like every little insertion hurts like hell. I left the appointment devastated, as the specialist just told me to eat birth control and ibuprofen.

I read that endometriosis often doesn't even show on ultrasound. She mentioned this, but there was no talk about investigating it further or doing s MRI or a laparoscopy. Again, I was left without getting help.

Now, I have to rely on public healthcare as I'm a student, and I don't have money for private gynecologist. Is there anything I can do, and could it still be endo?