AF symptoms or...?

It's 11 days from my last fertile day in my window, 6 days before my period is due according the glow. So far I'm feeling okay, just getting a very strange rumbling/vibrating sensation in my groin area, and when iv been sat with my legs crossed and get up to stand I have a crippling tightening/twisting feelin in my right side.. Is this just signs of my period coming yet again?!