Need Advice/Thoughts- What is This?

Ok ladies. I've been to the Dr and I'm pretty by the book normal. 26-28 day periods, I get all the CM when they come, but nothing happens each month. This month I thought we maybe hit it right. I currently have sore boobs and back pain. But I started spotting when wipe. It's this dark brown to this color blood. Did this happen to anyone before their BFP? Or is this just AF coming early? Thanks!