hello im 29 y.o ,about i month ago i had unprotected anal intercourse with my boyfriend there was no vaginal penetration what so ever ,my period is late now almost ten days , i had pregnancy home test about five times so far all came negative , i tried the morning sampling and i used different tests again all clearly negative , still im havin lower abdominal cramping and back ache my breasts seems fuller than usual no other symptoms , honostly im so nervous and im afraid of being pregnant , i have 2 questions is home testing aqurate and can large doses of vit c delay period???