I Am A 26 Year Old Female. About One Day

I am a 26 year old female. About one day after intercourse with my current partner, I noticed some vaginal bleeding. I dont think it is my period as I had my period already about one week ago. I am taking Yaz (in the past I was taking diane) and sometimes skip my periods. I'm not sure whether this could be break through bleeding from the pill, or something related to my anatomy or reaction to intercourse. The strange thing is, I was fine afterwards and the bleeding only started one day after. My current partner and I are both negative for all STIs. A couple of years ago when I had a different partner, I tested positive for clamydia. I treated this and my subsequent urine sample was negative for clamydia. I am wondering if it is possible to develop pelvic inflammatory disorder eventhough I receiving treatment for clamydia? Or could this be something else? A recent blood test showed that I have high levels of anti-thyroidal perioxidase antibodies. My doctor thinks may develop some sort of autoimmune thyroid disease in the future. Additionally, I have borderline neutropenia. The rest of my blood results were normal. I do not have any other symptoms and am otherwise healthy.