Suggest Remedy For Delay In Periods

I am very confused and not sure who to talk to since I don't want to call my gyno too early. I have a VERY normal cycle of 27-28 day while i was on the pill and even after for the past three months. I am currently a day late with my period and wouldn't normally think too much of it but i feel very different. My chest is sore and I have cramps (which i know might be a sign of my period coming) but a mix of lack of period so far and this odd fluttering feeling in my stomach which has gotten more dominent over the past few days. it sort of feels somewhat between a small jab or a little popping feeling. I have taken a clear blue easy test first thing this morning with negative results. Any ideas?