I don't think you have anything to worry about... It is most likely the stress of starting a new job. Even if you don't noticeably feel stressed, it is a huge change and your body can percieve it as stress.
I just found these statements in the book, "Taking Charge of Your Fertility" by Toni Weschler (an EXCELLENT book I highly recommend). Maybe it's more info than you wanted, but hopefully it will be helpful:
"There are several ways, though in which stress can indirectly influence fertility...A second way is that stress itself may affect when ovulation occurs. In fact, one of the most common causes of delayed ovulation is both physiological and psychological stress. This is because stress can dramatically affect the functioning of the hypothalamus, that gland in the brain responsible for the regulation of appetite, temperature, and most important, emotions. It also regulates the pituitary gland, which in turn is responsible for the release of FSH and LH (reproductive hormones). When stress affects they hypothalamus, the end result can be delayed emission of these hormones, which are necessary for the release of a mature ovum...
If stress were to affect your cycle, then one of 2 things would probably happen:
1. You would have a longer-than-average cycle, with ovulation ocurring later than usual and menstruation following 12 to 16 days beyond, if pregnancy did not occur.
2. You would have a long cycle, but wouldn't release an egg (an anovulatory cycle). If this were the case, the cycle could theoretically extend for months. Or you would have a long cycle followed by anovulatory bleeding...
While it is true that stress can prevent ovulation, it more commonly delays it. For this reason, it is especially important to learn to focus on the signs that indicate approaching ovulation. That way, if stress iscausing delayed ovulation, you can at least take control by identifying when you are about to ovulate, and thus take advantage of the most fertile time..."
Laura
I'm about 2 weeks late. I took a pregnancy test 3 days ago, and it came back negative. Can stress cause a late or missed period? I'm starting a new job this week. TIA!! 
The worst part is that my next month is usually heavier, I guess to compensate for the previous month. 
If you don't have a period next month, I think you should call your doctor, but for now I personally wouldn't worry.
