My period typically falls between the 24th and the 26th of every month. I'm two days late now, but have been experiencing typical PMS symptoms - sore breasts, cramps, overall achiness. I am sexually active, and we always use a condom, though I am not on birth control. These past two weeks, I have changed my eating habits and my exercise regime - at least thirty minutes a day, when before I rarely left the computer. I wouldn't say it's strenuous, but it's a definite change from my usual lifestyle. Could a new diet and exercise plan be pushing my period back?