What could this be..

Hi all, yesterday at 9dpo I had some very mild cramps and when I wiped some spotting, one wipe of red blood that was it, followed by today more mild cramps and the tiniest of brown spotting only seen when wiped which now seems to have gone to nothing and cramps have eased. I’m not due af for another 4 days from today....could this have been implantation or a very out of character and early af? I know implantation bleeds are rare but this has never happened to me before...