Nope this isn't possible.
Yes, one of the diagnostic criteria for anorexia nervosa is amenorrhea. Amenorrhea is the absence of a menstruation for three or more months.
Yes it sometimes does follow the regular cycles
Which medication you would take would depend on why your menstrual cycles are irregular. There are many possible reasons for irregular cycles, your doctor should run tests to determine the cause then discuss treatment options with you.
circodian
There is no specific age or time when a womans menstrual cycles will regulate, some womens cycles never regulate in fact. Even going through your teens and into your early twenties you will have phases of months or years with regular cycles then out of nowhere as your body changes your cycles can be thrown off. Things such as stress and ill-health can cause irregular cycles too. At very least you shouldn't expect regular cycles until adulthood, early to mid twenties.
Assuming regular cycles, probably around March 16th, 2008. Assuming regular cycles, probably around March 16th, 2008.
Biological Clock
circadian rhythm
yes if they can not control their menstrual cycles
It may take a while but your body should go back to your regular cycles.
You may be experiencing some non-menstrual bleeding, which can be normal. Especially if you are taking birth control and have missed a dose or two. Cycles are not always regular, and menstruation can occur every 3 to 8 weeks. If your bleeding continues for more than a week, it would be prudent to seek medical attention.
At 48 you're heading fast for menopause anyhow, so it's an open question whether you'll get any regular cycles again.