I've been taking tri sprintec for 6 months now and I have never missed a pill (the most that has happened is taking a pill an hour late due to work). I have unprotected sex every weekend and sometimes during the week doing the pull out method. All my periods while taking tri sprintec have been fairly normal although they did become thicker in texture (which I figured was normal) and a little bit shorter (5 days long). But this months period has been very light to almost no bleeding at all. I'm on my second day (which is usually the heaviest) and I feel like I've been spotting and I didn't bleed during the night at all . Which is very rare. I read about the implantation bleeding and now I'm starting to think that that may be what's happening to me although I've been taking my pills but I've never had this light of a period. So my question is if what's happening to me it's normal due to the birth control pills, or if I may be having implantation bleeding and am pregnant?