I have a clear 28 day period for the last 15 years now. My partner and i are TTC for more than a year. For the first time two months ago, my periods delayed without a reason for 6 days and tests came negetive. my gyn suggested medicines for getting the cycle, which i duly got. After HSG early this month, my periods are late by 3 more days and there are cramps on both sides of my lower abdomen . Tests are negetive and very disheartening. What could be the reason??