if you had a period after the exposure that you described, and had a negative pregnancy
test, there is no chance at all that you are pregnant. there is no need to worry at all. although it is true that nausea
and the other symptoms you describe can be associated with pregnancy, there are numerous other reasons why you might have these symptoms. they could be due to some stomach virus, or setting you are, it a number of other things. the symptoms will usually resolve in a day or two, so stay hydrated and take it easy and let it pass. if it persists beyond a few days, call your doctor and get it checked out. I hope this helps, please let me know if you have any more questions.