What does this mean?


My period was due yesterday but 3 days ago until today, I’ve been having this brown discharge first it was when I wiped after peeing now I can see it on my panties. It’s not enough for me to wear a tampon but troubling. This is the 4th day now and I’ve been taking the pregnancy test for a week , it’s negative. I’ve also noticed for my last 3 cycles I always have a brown discharge for days before my period. Is anyone experiencing or have experienced this?