I missed 5 days of my birth control pills about 2-2and ahalf weeks ago. I had unprotected sex and for about a week and a half have been nausea. I threw up the first couple days and then have been dry heaving daily since. It is just random nausea. The smell of certain things now make me gag when I never did before. I went to the dr yesterday and he did blood work. It came back negative. Could I be pregnant and it is not showing up because its too soon?