Advice/Venting

So AF is due in 6 days... for the past 4 days I’ve had very light spotting started brown and today is reddish. I don’t spot between periods and haven’t experienced this before. Of course I’ve googled everything on implantation bleeding and that’s what I’m hoping this is.... my only concern is that it’s lasting this long and might be something else. I don’t know what. 😔 I don’t have any other symptoms but usually don’t even get noticeable PMS symptoms. Anyways... just wondering if anyone experienced implantation bleeding for longer than 2 days, or if anyone has ideas on what this spotting could be.