What Causes Metallic Odour In The Vagina After Intercourse?

Hello, 15 years of age and unprotected sexual intercourse (his semen did not enter me) with a potential std carrier 8 months ago. Did not have any alarming symptoms right at the beginning of the sexual encounter although I seemed to have an onion smelling vagina right after and still occasionally get it also smells metallic sometimes (right now it does). My discharge ranges a lot at the moment and have had this for a few months now: grey discharge (not foamy), yellow discharge bit of green, watery discharge, brown discharge and once a really dark brown discharge that resembled the end of a period, clear sticky discharge, my discharge generally smells bad but not awful, I m not entirely sure how it s supposed to smell, and I get pus like yellow discharge. My vagina is itchy around the hole, outer labia and inner but not inside the hole. My perineum is also very itchy, and my scratching causes tears and bleeding in my perineum and my outer labia. This uncontrollable itching was present before my sexual encounter and I am not able to comment on my discharge as I don t really remember, I don t think I ve ever known what normal discharge is supposed to look like. Do I have an STD? I thought I had chlamydia as I didn t experience symptoms for a while.