i having unprotected sex with my bf on 12/10/2012. my bf discharge his penis before he ejaculate. my last period is on beginning of the month on 4-5/10/2012. my cycle usually will be 25 days. one week before my actual period, i will experience brownish and back ache. now it late, the brownish and backache only arrive on today 29/10/2012. am i pregnant? we still not ready for it..