If I had implantation bleeding 8 DPO and BFN 12 DPO.. What happened?

My theories..

1. Chemical? 😞

2. Maybe not implantation bleeding, but a tiny bit of brown blood for some other reason @ 8 DPO?

Has anyone else ever experienced something similar?

AF still not due for 2 or 3 days but with the BFN today (12 DPO) I think I’m out this cycle.. 😔

Best of luck to you all! ❤️