What Does Spotting Followed By Heavy Bleeding And Brown Discharge Mean?

Hi I had a period 4 weeks ago but it was just spotting, then 3 weeks ago i had really heavy bleeding for 7 days, now i have brownish discharge or bleeding not sure the difference really, but i think its more of a discharge and cramps. i am on birthcontorl and am breast feeding my son who is a year and 1 week old.