Gross: Brown Semi-watery Discharge

As my last post described, I started a new bc pill. I WAS worried about being possibly pregnant just because I had gained some weight only in my abdominal area, and the pill usually takes about a month to kick in (this is my first month on it). Well, this morning I wokeup with cramps and thought I had felt my cycle start. Turns out it's a brownish somewhat watery discharge. Does this mean anything in particular? Should I expect my flow to start? Or is my pill trying to do it's job by eliminating the flow altogether? Someone aid my curiousity please.