In a normal menstrual cycle, estrogen is produced in the first 14 days of the cycle and ovulation occurs on the 14 - 16 th day. This causes the ovaries to produce progesterone for approximately another 14 days. If pregnancy does not occur, the level of progesterone decreases and you get your periods.
In your case, I believe that you have not been ovulating in the last 2 months. As a result, there is no production of progesterone to maintain the cycle and the level of falling estrogen is causing you to get your period after 14 days.
Irregular ovulation is not uncommon after the age of 40 years, but this is usually temporary and the menstrual cycle tends to recover and become regular after 3-6 months.
If the bleeding is very uncomfortable or heavy, you can consult your Ob-gyn for a prescription of progesterone to be taken on the last 14 days of the cycle to cover up for the lack of progesterone in your own body. Taken for 3 months, this will regularise the menstrual cycle.
If your problem persists beyond 6 months, you will need to be thoroughly examained and investigations like ultrasonogram and blood tests for the levels of estrogen, progesterone, LH and FSH hormones as well as thyroid hormone carried out.
I hope this helps.