M.F.
You are 'technically' never 2 weeks pregnant. When everything is said and done, you considered 4 weeks pregnant.
It is possible to feel nauseous that early on, and also breast tenderness. I felt the same way with my first two pregnancies.
I knew I was pregnant as well because we were trying.
Take a test BUT just know that it may come out negative because you are so early. Also, word of advice I took a test with the lines...and I thought I wasnt pregnant because the second line was so faint. The next day I looked at it and sure enough TWO lines. So, make sure you wait enough time, and look at the test under GOOD lighting. and if its negative, try again in a week.