You are still very early along. So your relatively close to the implantation date. Basicly as your bodywas going through its normal cycle in the ddays before your period should have began your egg/ embryo implanted itself. It sent a signal to the rest of your lady parts. Ect ect but tiny amounts of the "blood" that would normally be released was trapped between the new growing amniotic sack and your cervix. Early on that is released in our discharge. As it is a bit aged it is brown in appearance. You may have this from time to time through out your pregnancy and it is not a cause for concern. However if it turns a bright red or the amount increases, about 2 tble spoons or it takes on a foul smell, burns or itches. Then contact your care provider as it may indicate a more serious issue.