If you have a normal cycle, it will be about or around 28 days long.
You typically ovualte mid way through your cycle. With a 28 day cycle, you would ovulate around day 14. You should have intercourse from day 10-18 every other day.
If you are on cd15, I highly suggest that you baby dance. If you are sick, it is not pregnancy related. IF you are pregnant, you would be like 1-5 days pregnant, in which case, the fertilized egg has probably not quite implanted. You have to wait until your next period is due to test for pregnancy in order to get an accurate and reliable result.
So, no, you are not experiencing pregnancy symptoms. Even if you were,
signs and symptoms of pregnancy are really no different than PMS. Early pregnancy symptoms include: fatigue, cramping, bloating....no different than if your period was on her way.