This happens to lots of women though--- they have an extremely long cycle out of the blue. Reasons
for a late period
include illness, weight gain or loss, stress, changes in routines, the holidays, new exercise regimes, etc. If you have trouble with your thyroid, this is a common cause of long cycles. So, I'd see if you get your period soon and if not, then go ahead and see your doctor. I had periods every three to four months for about a year and a half due to a slow thyroid.