I had a baby 7 months ago and had two regular periods once I stopped breastfeeding, but now I am almost three weeks late. I took two home pregnancy tests and they both came back negative. My husband had a vasectomy right after our baby was born and the last sample was negative for any living sperm. I have also start running two miles a day and lifting weights four times a week two months ago. Is it possible I'm pregnant? I don't feel pregnant but I have never missed a period without being pregnant.