What do you think??

So I had sex 2 weeks ago with on Tuesday or Wednesday and he came inside of me as well as Friday.  I have not been on birth control for about a month now... For the past week and a half I have been feeling very nauseas everyday to the point where I haven't been able to really eat so I have lost 10 pounds... I was suppose to start my period Wednesday/Thursday of last week and still haven't started. I took a pregnancy test Tuesday last week and it was negative I also took one today and it was negative.. I do have stress in my life... Do you think I have just taken the test too early to tell? Or they are false negatives? Or it's just stress? And should I go get a pregnancy test by a doctor or just wait until the weekend to take another one?