Lower back pains, abdominal cramping, four days late on my period! Last time I had sex was a week and half ago on Sunday twice and both times he ejaculates in me. And I had my period two weeks prior to that! I'm nervous because my period is usually pretty regular but I took a test yesterday and it was negative! I also keep getting a nervous butterfly feeling but in my pelvic area, could I be pregnant?? Is it too soon to take a test?