Thick vaginal discharge of green colour

I have been getting dark brown discharge since about two weeks I think, however it's not exactly under my vagina, it's actually kind of on the backside, where the anus is. I got the brown discharge first, and now I've been getting dark green discharge, that's near the back side too. I am a virgin, and I'm 18 years old. I get irregular periods, like literally after six months, because I have a condition called Acute Porphyria. I am very very very scared, and I don't know what to do. Today, I got vaginal pain the whole day too. Could it possibly just be a sign of PMS? Or should I go see a doctor? Has any of you ever experienced something similar? Please please help me out. :(

I am just really worried that it's cervical cancer or something!! :(