Hello, i got my period on time (28th day). Today i am day 4 and my period is completely finished. Usually ends on 5th sometimes 6th day. Also on a 2nd day i had a pulsating pain in my lower left abdomen that went away after i took a pain killer. Before i took a pain killer pain was eased by laying down and worsen by certain movements. What can cause this, for me unusual situation?