I am 16 years old. i recently had unprotected sex 4 times with my boyfriend on the 9th of feb 2013. he came in me all 4 times we had intercourse. i am not on birth control and my lower stomach has been cramping all day and my nipples are very tender and cracking, they almost feel like itchy, but stinging. when should i take a pregnancy test? and what do you think my possibilities of being pregnant are? thanks