Possible pregnancy??

Courtney
Its been 2 weeks and a 2 days since I had unprotected sex. Saturday night I was cramping horribly and felt dizzy. In the past week I've been hella sleepy and lazy. I was supposed to start my period today and it hasn't come yet. I took a pregnancy test and it was negative. Any advice??? Or has anyone experienced this before? Note: I've never had cramps before my period.