I never nicknamed my period, but most women do, and the most popular name is "Auntie Flow," or "AF." Most women can tell you when they expect the visit, but it's also perfectly normal for your period to fluctuate.
Let's review the typical menstrual cycle again. Day 1 of the cycle is the first day of full blood flow. That lasts from 4-7 days typically. Then the follicular phase because when the follicles on the ovaries grow, leading to one dominant follicle that bears an egg. Somewhere around day 14, the egg ovulates, and the luteal phase begins.
It's called the luteal phase because the ovary produces a corpus luteum from the site where the egg erupted, and the corpus luteum produces progesterone. This phase lasts up to day 28, when the cycle starts over again.
If you get stressed in the follicular phase, your body may decide to prolong the phase a bit, resulting in later ovulation. The luteal phase will pretty much always be 14-15 days. Stress does not affect the luteal phase. Once you ovulate, if implantation does not occur, your body will stop producing progesterone and shut the store down.
What makes your period late? I have already mentioned stress as one factor that can trigger a late period by causing late ovulation. Over-exercising that leads to a decreased body mass index and body fat will also interrupt normal menstrual cycles, but in that case, ovulation ceases or becomes irregular. If you don't ovulate, you won't menstruate.
Polycystic ovarian syndrome, or PCOS, also leads to irregular menstruation. Obesity is also common in women with PCOS, and losing weight can often help the disorder.
Even a perfectly normal, healthy woman can miss ovulation occasionally. Of course, that is usually due to stress early in the cycle. The next month will be back to normal usually.
And, of course, let's not forget pregnancy as a cause for a late period. Think back....if you had intercourse about two weeks ago, you could be pregnant. You can test as early as the day of your missed period, but to get the most accuracy from a pregnancy test, wait at least 2 days. By then, AF often arrives!