Period still 5 days away

Last night before bed, I noticed some brown blood mixed into my CM. Today is still 5 days before I expect my period. My cycles are generally very regular and if I do have an off cycle, it’s usually because my period is a couple days late. But never early. Since this bleeding started at 6 days before expected period, and what would’ve been 8/9 dpo, do we think it could be from implantation? I know implantation bleeding only happens to like 10-20% of women, but this is very strange for me. I got a negative test this morning (9/10 dpo) using FRER. Do we think it could be implantation?