I am 40 years old...I have been tracking my period for the last 6months and I have started my menses every 14 days. I stay on for 8 days.Is this normanl?

Hi,
You are probably in perimenopause, also called the menopausal transition, is the interval in which a woman's body makes a natural shift from more-or-less regular cycles of ovulation and menstruation toward permanent infertility, or menopause.
Women start perimenopause at different ages. In your 40s, or even as early as your 30s, your may start noticing the signs. Your periods may become irregular — longer, shorter, heavier or lighter, sometimes more and sometimes less than 28 days apart. You may also experience menopause-like symptoms, such as hot flashes, sleep problems and vaginal dryness. Treatments are available to help ease these symptoms.
As ovulation becomes more erratic, the intervals between periods may be longer or shorter, your flow may be scanty to profuse, and you may skip some periods. Early perimenopause is defined as a change in your menstrual cycle length of more than seven days. Late perimenopause is characterized by two or more missed periods and an interval of 60 days or more between periods.
Treatments to regulate periods include low dose oral contraceptive and progestin therapy.
I suggest you make an appointment with your gynecologist to discuss perimenopause and also, to check that you are not anemic because of the frequency of your menses.