My nipples hurt, what does this mean?

Okay well about 2 weeks ago me and my boyfriend had protected sex. and then a few days after that we had protected sex again.Here it is about two weeks later and I am freakin out that I could be pregnant? I get my period on the 19th and it is the fourteenth and my nipples are hurting and I was cramping the otherday.Yes it was protected and I am still freaking out that my period may not come.Should I be freaking out or what do you think this means? I`m 15 by the way and am scared abnd am hoping im not pregnant.PLEASE HELP could my nipples be hurting from stress or because my period maybe close or what?????????