Scans for Endo

JJ
I have been researching Endo for around a year now and I have MANY of the classic and not so classic symptoms. So I went to my doc and spoke to her (she was a bit of a sceptic to my cause) but as I'm getting older (nearly 30) she agreed to help me. She referred me for internal and external ultrasound scans. From my research these cannot tell if there is Endo present / give diagnosis. 
Can anyone answer why I would be sent for these if it is not a proven way to diagnose Endo? Is it a routine - first resort type of thing before they will consider the laparoscopy? 
It's stressing me out the thoughts going through my head and I can't sleep with having so many questions that need answering.