I had unprotected sex while I was ovulating. My period did not come the morning I expected it, so I took a home pregnancy test at 14 days past ovulation and it came back negative. Three days later my period started. It was the same flow, but lasted two fewer days than normal. Since then my breasts have been unbearably sore (I haven't been able to keep a bra on) and I've had menstrual-like cramps on and off throughout my cycle. I was supposed to get my period yesterday morning but I have not gotten it. Should I buy another home pregnancy test?