I had unprotected sex on a Friday and right after my period started it was time for it anyway it was heavy and normal like I'm used to except on the 4th day of it it abruptly stopped no slowing down just stopped and I keep getting feelings of I guess you would call them butterflies and I'm not sure why it stopped like that and my periods always go from a Friday to a Friday. My lower abdomen is a bit tight feeling. Help Please?

