I’m confused

Kaitlin • Married, mama to 3 ❤️

I’m not supposed to go get my period for 12 days. I had sex twice in my fertile window (not preventing pregnancy.) my fertile window ended yesterday and I started spotting, so I thought maybe implantation bleeding, threw a pad on & this morning I woke up with a pad full of old blood. Everyt I move a bunch comes out. No clots.