Hi, I had my last period October 22nd and two weeks after had unprotected sex, just about the right time of my ovulation. About 5 days later I started sporadically cramping and having lower back pain which is very unusual for anything routine in my cycle. I took a blood test as well as OTC urine tests and all came back negative. The nurse at the doctor's office even said it was too soon to find out. Could it be pregnancy or does it sound like another health-related issue?