chances?

July 28th the condom broke and August 1st the condom broke again. he wasn't inside of me either time and like 3 days later i started BC pill. since both dates i've had a period (was normal) and the3 preg tests i've taken were negative, i actually took one sept 3rd before bed and one Sept 4th when i woke up and both were negative. i'm about to take another one tonight or tomorrow morning just to make sure,

realisticly i know there's always a chance, albeit small, but with the period and all tests negative- i'm okay right?