Is A Delayed Period After Unprotected Intercourse Normal?

Mam, I got married on 27th june 2010 and my wife got period on 30th june morning. I had a little suspicious about unprotected sex and thought that she might have got a pregnancy. so she had taken i-pill on 5th july, But she had unexpexted period on 11th july. Now on date 4th august, I have checked pregnancy test and i found that she wasn't pregnant but till now she doesn't have her next period !!! what can we do? Please suggest your valuable suggestion !!!! thanks Her age: 27 My age: 29