3 days before period

Is it possible to get pregnant 3 days before period? Me and my partner had unprotected sex and he came in me 2times and it was 3days before I had my period but before that I feel something unusual like headache, backpain, dizzyness, cramping, and sometimes im feeling like nausea.. Is it possible that im already pregnant even I had bleeding which is I dont know if it's my period or what..