Depo shot

I had my first depo shot on March 24,2015 an I been have regular cycles since I been on the shot. Last month I got my regular period which last four days on June 8 an I recently missed my 12 week appt on June 16 an I started spotting on June 21 and red spotting the next day,the next day brown spotting an then it stop an here it is July an no aunt Flo