Girlfriends period is 2 days late does that mean she is pregnant?

She could be, the only way to know is for her to take a pregnancy test. There are other reasons for a woman to be late though. Stress, change in diet, extreme weight gain or loss, working out a lot more then usual and at least once in a womans cycle life she will be late or miss a month. My sister in law missed 2 months in a row and she wasn't pregnant. Good luck and I hope it works out how you want it to.