What Causes Brown Vaginal Discharge While Having Endometriosis And Ovarian Cyst?

So..I had sex and after a few times I started to get a burning inside my vagina. Then I started to itch and get a brown discharge. I have endometrosis and cysts on my ovaries. I have been having pains in my pelvic area badly for weeks now. And no medicine will help. My aunt thinks its either an std or Im pregnant. Im so scared to talk to my parents. Will you please help?