Help! Lol

Hey guys. I need some questions answered. My fiance and I had, had sex on the day I was ovulating it was like a 4.5% chance or whatever. We didn't know I was ovulating until I checked. So I am now 12 days late and we're kinda thinking I might be pregnant. But there are a few things im wondering about. For the past like 5 days I have had minor cramping. Then i would get this pinkish redish mucus discharge. Now I am having cramps a little bit more but not that intense with dark brown almost black blood coming out. I know it's considered "old blood". But why is this happening. I can't find answers on Google and I don't have an OBGYN at the moment.