I hd sex a week & five days after my period (once),is there a possibility that am pregnant?

It depends on how close you were to ovulating. When isn't the only important factor. If it was unprotected, then your chances increase exponentially. Confirm with a pregnancy test. I said a lot more about avoiding pregnancy here:
http://www.ehelp.com/questions/10442978/could-i-be-pregnant

In many responses, Rob has cited this information: "The web page below has nine links at the bottom. If you understand all of the information on those pages, you will clearly understand how it works and the risks of different behaviors."

Planned Parenthood:
http://www.plannedparenthood.org/info-for-teens/pregnancy/am-pregnant-33831.asp