I Had Unprotected Sex Yesterday And I Immediately Took Ipill

I had unprotected sex yesterday and I immediately took Ipill within 5 hours of inter course but I'm not being able to trust the pills. Should I just wait for my period or take an another pills tomorrow morning as I still got some time remaining to make it 72 hours !! What are the chances of me being pregnant as it has just been 13days I had my last period ??