please help.

Emma
so me and my boyfriend had sex a week after my last period. we used a condom. but before he put the condom on we had contact down there with each other. and I read online that there is such thing has pre cum or pre ejacuation and could get your pregnant. is there any chance I am... currently freaking out. supposed to hit my period tomorrow but really haven't had signs of my period. 
my cycle is 24 days. 
I had sex on my 12th day 
and I am not on my 23rd.