Pregnant?

So my period is late by 5 days... I was supposed to get my period on the 12th, my boyfriend and I had unprotected sex on the 8th and the 9th.. I took a test the day I should have gotten my period (the 12th) and the 16th and they both came out negative... Is it too early to tell? If it is how much longer should I wait to take another test?