Pregnant?

I know y'all aren't doctors or whatever but I need help deciding if I'm possibly pregnant..

I had unprotected sex 10/30 and for the past week I've been nauseas and certain smells make me sick. I've had lower back pain and a little bit of cramps. I'm not due to get my period until 11/21. This morning I took a test and it was negative. Was it too early to test? I can't think of any other explanation for the nausea. I feel completely fine otherwise. It doesn't feel like the flu.