I had some foreplay with my girlfriend and ejaculated on her body.
It was the day when the calender showed pregnancy chances medium, her expected period date was 10th of November, bet she hasn't had any till now, I am worried whether she has become pregnant as the sperms may have by mistakenly entered her vagina while washing!!
I am very much tensed!!

It rare but it is possible. She should wait another week and then take a pregnancy test.

If you are "very much tensed" maybe you shouldn't be playing these games until you are ready to be a father.

While led pregnancy this way can happen it is very rare. Her period might just be late. It happens to everyone at least once.