Im on birth control, but in the third week, i missed a pill, and had unprotected sex. now im having alot of symptoms of pregnancy... ?

Can do a preg. test: Any fertile woman having sex must accept her ability to get pregnant, if she chooses to have sex. It can be hard to tell if she is pregnant because some of the symptoms seen in early pregnancy can also happen in non-pregnant women. A urine test gives a reliable result if done correctly, about 3 weeks after sex (3 weeks after when conception might have occurred), or 1 week after missing a period.