Pregnant or Not?

My period came on July 15 2016 and finished on the 19th, which it usually last for 5 days. I had unprotected sex with my fiancé on the 22nd and then again on the 24th. I was suppose to start my period on the 8th of this month but missed it with 4 days, took a ClearBlue Advance test and came out to be negative. My period came on the 13th of this month. My question is, why am I not pregnant?!? I am NOT on birth control and did NOT use a condom? Could I still get pregnant after my period is over? Help!