TTC! What is happening?

12/11 was my last period, and I ovulated 25/11 (est) .

On the 6th - 8th I had light medium bleeding less than a period more than implantation and nothing on the 9th which the day my period was due, now the 10th & 11th I’ve been spotting when I wipe. I’ve taken a pregnancy test today (16dpo) and it’s negative . Did my period come early? Was it a chemical? Is pregnancy still a possibility? If someone else has had similar happen please comment ty