I Had Unprotected Sex The 5th Day That I Was

I had unprotected sex the 5th day that I was using nuvaring and my doctor told me to use protection during the first 7 days.. I've been feeling really sick and my breast have swollen a lot . I've taken three pregnancy test and they all have been negative. I just took my nuvaring out because it has been three weeks.. Is there anyway that I could be pregnant?