Am I pregnant??

My fertile window was 28-4 and I had unprotected sex twice but he pulled out. My period is supposed to start on the 17th and yesterday I started spotting light pink/brown. I've been cramping my boobs have been sore for about a week and I've felt dizzy and my nose has been stuffy. I've had horrible headaches. Could this be implantation bleeding or just early period and pms?