What Causes Brown Spotting From Vagina?

Hi, so I ve been having sexually active lately, and my period should be coming in the next week. I ve noticed that when I go pee or poop, this brown liquid drips from my vaginal area. It looks like it has tiny specks of dirt in it and when it hits the water it spreads apart. I have no idea what it is and I have no pain when I use the bathroom