13 dpo

I’m currently 13dpo and my period is expected tomorrow. However on 11 dpo I had light brown spotting - only viable on toilet paper. It stopped and didn’t turn into anything more and then in 12 dpo it came back again same light brown spotting has been continuous into today at 13 dpo. I took a test and it’s negative. When AF usually comes I never spot before it and it’s never like this. Anyone experience something similar? Can you share your experience.

Thanks!