brown discharge before period

Kelsey
I took plan b last month (because I accidentally missed a pill) like 3 days before my period which only delayed it by 1 day. So this month I took my BC at the same time everyday like Your supposed to. I've had sex but it still was all with a condom even though I am on birth control. None broke. It is a few day before I am supposed to g et this period and I have been having brown discharge with some cramping. Is that normal? Is that implantation bleeding? Should I worry? Is that because of the plan b?