I had my normal period and had sex my last day there was little to no spotting. I am pretty sure I took tampon out when I checked I found nothing and am having no symptoms of leaving my tampon in but the next day I went to the bathroom I started bleeding again then I have just seen light pink on the paper when I use the bathroom it has only been about two days I am on birth control and have been taking it faithfully so I'm not worried about being pregnant just worried something else is wrong, should I be worried I normally am off on the last day of my green B.C. pills but I am spotting very light could this be because of the sex?

Yes, sometimes there can be some spotting after sex... even more likely since you were right at the end of your period.