Going to the Gynocologist

Hey everyone! lets get straight to the point, basically I've been experiencing pains in my rectum during my periods and the GP said the symptoms were those of potential endometriosis so he's referring me to the gynaecologist.
I'm only 15 and am incredibly worried and scared about this, does anyone have experience at the gynaecologist and wants to inform me on what happens when you go there?
i really dont want my genitals to be examined by a complete stranger and worse of a male gynaecologist because that would be so awkward. i would rather live with this pain and a risk of endometriosis than show my privates to a complete stranger, i was also reading online and apparently they stick some metal stuff up your vagina to check it out and im actually so worried, i find using tampons painful and i dont really want my hymen to tear. Apparently im still too young to be referred to a proper gynaecologist so it might be a children's doctor and im so scared!!! can i request for a female doctor?
Ahhh, will i have to like strip or something and what if im on my period on my appointment and ughh.
can anyone help me out please!! it will be much appreciated.