Its worth knowing if you have had unprotected sex during during this period? If yes, its a possibility you might be pregnant. However, at age 40, its not rare to have some alterations in the menstrual cycle, wit either delays in expected days or lesser than expected amounts of mentsrual flow. Its interesting if you could do a pregnancy
test to rule out a pregnancy.
The symptoms you describe are classical symptoms constituting what we call the premenstrual syndrome
. These are signs noticed most of the time before menses. In your case, I would advise you do a pregnancy test, if its negative, the you should be expecting your menses or it should be a skipped period. In case the flow is foul smelling, profuse, you are feverish, intensity of pain increases or you really become worried, you might consult a gynecologist. As we approach age of menopause
which differs from woman to woman, such alterations are common, and I think you need not really bother much at this stage.
Hope this helps you,