Anatomically, your ovaries are aging, becoming old and wrinkled and do not release an egg every month although you still have periods. There will also be a slight decline the production of Testosterone.
Some women experience heart palpitations.
Moods may swing from gloriously happy to depressed to confused, angry and fault finding, crying for no apparent reason, or you may be forgetful, can't find the right word or lose your keys. Before you buy a package of Attends, start doing Kegel exercises, they really do work if you do them regularly and frequently. Unbeknownst to you, there may be calcium coming out of your bones leaving them brittle and porous and they break easily, especially your hip bones. This is not as easy as it sounds, you are going to have to alter your diet, reduce sugars, coffee and tea and colas, high fiber, lower carbohydrate, many more fresh fruits and vegetables and less red meat. Soy, found in Tofu or Soy Milk has a mild estrogenic effect but it would take a lot of soy to meet your needs.