I'm not Shelly, but I think that is yeast discharge. What is your diet like? If your diet is good but recently improved, maybe you are breaking up old yeast. When my diet used to be bad, sometimes after heavy aerobics I would get a brown discharge the next day. I assumed I was detoxifying and sometimes that has happened to me before my period too, but since my diet is cleaner by far, this is rare or I have some clear mucus before my period.