Morning After pills, Bleeding, and worrying.

I'm fifteen and female, my period is still irregular but more than 30 days estimated. I recently had my period on the 20th of April 2010, and it ended on the 28th of April 2010. On the 28th of April in the afternoon, when my period had completely ended, I engaged in sexual activity. My boyfriend and I were mucking around, he jacked off and ended up cumming on his hand, he also said he had wiped it off and that they were dry, a few minutes later he proceeded to finger me. Still being scared under 48 hours I took the Morning After Pill. Now 6 days after engaging in sexual activity I have found out that I have bled, my flow is usually heavy, or almost heavy, and today I experienced light bleeding, not spotting but a patch on my underwear. Itwas brown to dark brown in colour, after experiencing this, I read about implantation bleeding, and am now very concerned whether I may be pregnant, I had also read after that happens it only lasts for 24-48 hours and that it should not be noticeable only when wiping, and which is what is happening now after I have bled lightly. I have also read this is the affects of the morning after pill, could I be pregnant?