Slightly green discharge

So last night my boyfriend and I had unprotected sex. (I’m on the pill.) he didn’t come inside. Immediately after sex I was cramping very badly. I woke up around 3:30 AM, cramping and I felt a little nauseous. This morning, I wiped and saw the tiniest bit of blood and my discharge had a very slight green color to it. And no major change in smell... any ideas? My period isn’t due until the 17th.