I am seventeen years old, and a couple of days ago I experienced a small amount red spoting that only lasted for an hour or less, and it was exactly one week before my period is scheduled. I have been taking norgestimate and ethinyl estradiol pills regularly for the past couple of years. Last month I was about eight hours late on a couple of pills, but this month I have taken them all at roughly the same time of day. I have have sex without a condom on a relatively regular basis, and have never experienced spotting or breakthrough bleeding before. However, I have noticed that as I get older my periods become less regular and my PMS gets worse. I have not noticed any other early symptoms of pregnancy besides a little bloating, but I have a cold and I've been particularly stressed lately. Could this just be stress and illness, or is it likely to be implantation bleeding? Replies are appreciated.