HELP ...

Gabrielle

Last month i had my period on the 18...We did the deed (feb..11,14) ....I was originaly suppose to get my period on Valentine's day. . Nothing then calendar said 18.. nothing .. took a test friday morning. . (NEG) -.- ive been feeling nauseous and a headache. ...

And its the 22 did it today. . And still no period. . When do i take the next test, am i pregnant? ?