Confused...

My last period was 5/18. My period was due 6/14.. Only thing I have had was thick white creamy discharge. No smell or burning or irritation. Today 6/16, I went to the bathroom and noticed some pink/brown mixed with the white discharge. An hour later I wiped and saw a little more red. So I thought my period was coming. Put tampon in at 11am. When I took it out around 4pm there was mostly brown discharge and a small amount of red at the very top. It's not 9pm and I haven't had any more bleeding except a few drops when I wipe still. No cramps which I usually get very bad when I am starting my period. Not sure if this means I'm pregnant. I had taken a test yesterday from the dollar store and it turned out negative. Any one had this happen before? Were you pregnant?