So you missed a period. Or two. You think to yourself, “I’m too young for menopause. Right?”

Not necessarily. Early menopause, between the ages of 40 and 45, affects about 5 percent of women. Premature menopause, before age 40, affects about 1 percent of women.

You are said to be in menopause if you have gone a full 12 months with no menstrual period. That’s when your ovaries stop making estrogen and progesterone, the female hormones necessary to maintain your menstrual cycles and fertility. For most women, menopause occurs naturally at about age 51. With increasing life expectancy, many women will spend up to 40 percent of their lives in the postmenopausal stage.

For some women, menopause is induced early because of treatments needed to save their lives, such as surgery, chemotherapy or radiation. For others, it’s genetic conditions, autoimmune disorders or even unknown reasons that bring about this change.

From disrupted sleep and hot flashes to dry eyes and weight gain, menopause symptoms can range from annoying to serious. But if you are experiencing these things in your 20s, 30s and early 40s, it may make you feel like you’re growing old overnight — and aging beyond your friends.

And here’s the thing: The signs aren’t always clear when you are entering premature or early menopause. Maybe you’re moody, but who isn’t? Maybe hot flashes have started, maybe not. In fact, you may not even realize how a hot flash feels. A hot flash is a sudden feeling of warmth that spreads over the body and is usually most intense around the face, neck and chest. Some women may feel a mild flushing. Other women end up soaked in sweat and need to change the bed sheets.

So, without a big neon billboard saying, “Welcome to Menopause,” what should you do? Here are five things you need to know about early menopause:

1 It’s not too early to talk to your health care provider. If your periods change significantly (become noticeably longer or shorter or vary markedly from your usual schedule) or stop altogether for three cycles before age 45, make an appointment for an evaluation. Missing periods can be a sign of other health concerns too. If you are experiencing premature or early menopause, you’re at risk for multiple long-term health consequences, including heart disease, dementia, Parkinsonism, and osteoporosis if you do not take hormone therapy, aptly termed hormone “replacement” therapy under these circumstances. Your health care provider can help determine if you are, indeed, experiencing premature or early menopause.

2 Hormone therapy is vital for lessening the long-term health consequences associated with early or premature menopause. Unless there is a clear reason to avoid hormone therapy in your particular situation, using hormone therapy at least until the natural age of menopause (51 years) is recommended by the North American Menopause Society and other professional medical societies. However, hormone therapy may not alleviate all of the changes associated with early estrogen loss, particularly mood changes and sexual dysfunction.

3 Your family plans may change. If you wish to have a family, you may need to consider options such as freezing embryos or eggs. If you had planned to have children, you may need to allow yourself to envision a new dream, such as building your family through in vitro fertilization with donor eggs, adoption or surrogacy.

4 You can get your sexy back. If you are experiencing low sexual desire or vaginal dryness, talk to your health care provider. Hormonal treatment with estrogen may help with vaginal dryness. For some women with low sexual desire who go through menopause early or prematurely, testosterone therapy may even be appropriate. And talk to your partner too. Good communication is associated with higher sexual satisfaction.

5 You may need extra support. If you are in early or premature menopause, you may need extra time and support to come to terms with your diagnosis and the consequences, including the potential long-term health impact and loss of fertility. Sharing your concerns with your partner, friends and your health care provider or psychologist can help. Understanding what is happening to your body and what you can do about it is key.