i've been regularly taking the bill since january 2006.
last june and july, i began spotting a week before my period. the spotting was very light and it was like a red blood color.
last august, september, and this october, i have been spotting again a week before my period. the spotting is of a darker brown color.

why am i all of a sudden starting to spot after a little more than 2 years of normal regulation and spot free while on the pill? what does that mean?