Possible Pregnancy Symptoms: Period Irregularities & Breast Tenderness

Question
I am 17 years old, I have no children and the first day of my last period was September 6,2005. Well me and my boyfriend had unprotected sex. While we were having sex, I was on my period. It wasn't a heavy flow but my egg hadn't dropped or came out yet. The next day, my period just stopped. I didn't have any discharge from my period or anything. Now I think I am having symptoms because my breast hurt when I squeeze them and I get tired easily. Could it be possible that I am pregnant?  

Answer
If your last period started on September 6, you would not have ovlated until September 19 and could only have conceived if you had unprotected sex on September 18,19,20, or 21. You could not have become pregnant on any other day of the month. You could not have conceived while you were having your period. You were due for your next period on October 3. If you do not get your period by October 10, take a pregnancy test. Then you will know for sure.