I had intercourse around 6 weeks back , had taken emergency pill and got withdrawal bleeding too after 5 days. It's been more than a month now ,I didn't start period. My period has been delayed, I show quite a few pregnancy symptoms too like sudden changed in my body, I have gained weight all of a sudden, feel bit nauseous sometimes, etc.. but then I tested today for pregnancy and it was negative. Why does my periods delayed then?