Late Period,negative pregnancy test?

Okay,so saturday makes two weeks since I had unprotected sex with my boyfriend. I took a pregnancy test last saturday because I was having some cramping and light bleeding. The test said negative so I didn't think about it. I woke up this morning extremely nauseated and realizing the date. My period usually comes around this time. Im the type of girl that will cramp like crazy before her period comes. It never fails. Is it too early for me too start feeling like this if I am pregnant? What does this sound like too you?