Periods after d and c

D and c in late January, had a normal period 4 weeks after that and I'm now in the middle of what should be my second period. For the last 4 days I've only had brown spotting, nothing crazy. Is this my period? I thought periods mean red blood..? Took a test to be sure yesterday and was a BFN. Will call the Gyno soon if this continues... Any help out there? Has this happened to anyone?