late period....but negative test

I'm 15 years old and I've recently had unprotected sex. my period was supposed to start last Thursday so I took a pregnancy test Sunday and they were both negative. but I still haven't started my period. on Thursday I'm taking another home pregnancy test and then going to a pregnancy clinic to get checked by a doctor. if I am pregnant I'm not sure if I'll keep it. I'm really against abortion but me & the guy who may have gotten me pregnant both agree it might be best. but my best friend thinks I should give the little guy a chance....any advice. please don't judge or hate. I'm already stressed as it is! thanks!!