Ive been on the pill for about a year now. Two months ago I started a new brand. The first withdrawal bleed on it was normal and fairly heavy just like mine always are but the second months bleed that I got last thUrsday was not. It usually starts off light tr first day heavy second and finishes light the third. This one was just very light brown spotting for 2 days. I'm getting worried, I've never had a bleed like this before- could it be implantation bleeding? I got it on the day that I expected it and I havent missed any pills. I'm on the combination pill (aviane- generic for alesse) but I did take one pill in the second week 9 hrs late.