7 days late then started Spotting

Kristin • 18 years young⚓️ Mommy to the most amazing lil man.☺️ In love with my best friend.
Okay so I was 7 days late for AF! Yesterday morning I started spotting it's mostly been brown but some pinkish. No actual red AF blood. I'm barely even spotting today. I took 2 tests a few days ago & got bfn. Could this be implantation or old blood from last AF?