Light bleeding brown blood 3d before my placebo week, constantly. ive been on the pill for over a year but switched to yaz 4mo ago, is this a worry?

BCP bleeding: Most bleeding from a course of oral bcp's which occurs prior to the end of the "active pills" is due to not taking the low dose active pills at the same time (within the hour of the previous day/evening) , or missing a day in the series. Stop the pills now, and begin a new pack, and remember to be punctual when taking the active pills to avoid this kind of bleeding.