I'm 18 and I have been sexually active. My last period was on Sept. 3 and it was supposed to come last Oct. 3 +/- 3 days. Ive had sex twice last september and both times my boyfriend and I used condoms. He pulled out before finishing. I took a pregnancy test yesterday and it was negative. Ive been very stressed these past few weeks and my sleep patterns have changed because of the exams and requirements at University. My breasts are not sore nor I am tired. I have back pain though but it's probably because I slipped and fell on my ass. I also felt cramping on my lower abdomen earlier but it's gone now. Is there a chance I could be pregnant? Please, someone help. I'm not ready for a child right now.