What Causes A Missed Period After Having Protected Sex?

I had protected sex July 19. That night we used 2 condoms. Both did not rip or anything like that, because we checked well afterwards. Now that I think about it, I don t think he pinched the tip (if that matters). But at the end of the night both condoms were in perfect shape. It is now August 27 and I m freaking out. I ve never missed my period since I have a regular period. I don t know what to think. I m stressing.