I am 16 years old, I had unprotected sex on June 23, 2012. Three days later on June 26th,2012 I had my period, but it was only 3-4 days. When it is usually 5-6 days. If I am pregnant, I would be 3 weeks and 1 day. But all today and yesterday I have been sick to my stomach, moody, tired, my boobs hurt soo bad and my nipples are really itchy. I have been having some very slight cramping in my lower abdomen. My period is supposed to come in 10 days. But I never feel like this, this early before my period. Could I be pregnant?