What Causes Brownish Vaginal Discharge?

Hello! I'm 21, 122lbs and recently, I noticed a dark beige vaginal discharge. I haven't had sex but I have masturbated with sex toys. I also know that I have pcos and irregular periods (sometimes they come twice a month and such). Usually the discharge that I have though is white or dark brown (usually after periods so I assume it's old blood) but I've never had this kind of colour. There was no hint of blood or so, just a really nasty colour. Could it be some kind of fungal infection? Or..?