Is my girlfriend pregnant?

My girlfriend is on a 28 day cycle. Her period started June 24th. We had sex on July 3rd, and the condom broke. I didn't ejaculate, but there may have been prejaculate (I showered and peed at least once before we had sex though)and my condom touched her vagina for about 2 seconds according to her. I didn't go in. We then put on a new condom and started again. On July 14th she began bleeding, assuming it was her period. She said it only lasted a few minutes then it stopped. She didn't start bleeding again. Today is July 22nd, the day she is due for her period, but she hasn't got it yet. So far she's shown no symptoms, except her back hurt for a bit one day, and she had a headache once. She is not on any kind of birth control.

Do you think she is pregnant?