I had my period dec. 1-5. My fertile window was the 12-18th. We had sex on the 13th. On the 16 I had cramps and constipation, headaches and fatigue that lasted to the 24th. On the 24th I started to lightly bleed until the 28th. My periods are always very heavy this was much lighter. It is now the 29th and there is no bleeding even though my period was due to start today. I am feeling some slight pressure in my stomach. Was it just an early period or could I be pregnant?