What Causes Vaginal Discharge Instead Of A Period?

Hi, my cycle is 30 days. On the day I am expecting my period, I recognized a brownish discharge from my vagina when I wiped. I put on a pad and checked 2 hours after and there was just a slight glazed of brownish pink discharge. The next day there was not any discharge. I had no cramp or pain. Can you tell me what is going on?