thanks, smiley214 and turtle21.
you don't have to throw up in order to be pregnant!!! Lots of women get pregnant, and have morning sickness but never actually throw up so there is still a chance that you might be pregnant!! Take care of your body, and treat it as if you ARE pregnant until you know that you're not. So don't drink any alcohol, smoke cigarettes, etc.
As far as the chances of you being pregnant, it's actually possible for a woman to become pregnant even if she has sex while she's on the last days of her period. Sperm can stay in the women's body for several days and still fertilize an egg. The chances of that are very slim. BUT you did mention having sex 3-4 days after the first time, in which you could have gotten pregnant if it was unprotected. When you miss your next period, you will know! Until then you need to just take care of yourself. I'm not saying you are pregnant, but better safe than sorry. The chances that you're pregnant, however, are slim so you're probably just nauseated for a different reason. I've been experiencing nausea the past couple of days due to a cold I'm getting over.
Good luck!
its probably ur cough but if its still goes on for more then a week n start vomiting 2 u should probably get a pregnancy test.