Help need some advice!!

Me and my bf had sex on October 13 and he said he pulled out but I'm not sure and I know I should have been more careful! I started ovulating October 21-27! My period was suppose to come on today but it hasn't... I have been stressing and took a pregnancy test this morning and it said negative! Could I still be pregnant even though I still not have had implantation spotting or any pregnancy symptoms  I'm 19 and just need some advice!