I am healthy, and I have really consistent 28 day cycles, but I am 2 days late. I have had unprotected sex right around ovulation, but just once. No unusual stress, excercise or weight loss. I tested neg. on a HPT today. What's driving me nuts is that I have felt like I'm about to start for more than 6 days. Cramps little different than normal, achy pressure, headaches and sensitive nipples. Could that test be wrong, or did i somehow ovulate late?