Period is late

My boyfriend and I have been having sex for about 2 years now and ALWAYS used a condom. We never even tried it without one. But now I'm getting worried that I might be pregnant because my period is late by 8 days and I've been nauseous to the point where I can't stand. Anyone have some suggestions on what I should do? I'm 18 and we should be moving in together because he has a really good job. I'm just scared.