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7 Signs Your Period May Come Tomorrow

Written by:, PhD, Founder and Inventor of the Proov test — the first and only FDA-cleared test to confirm successful ovulation at home.

Have you been here? It’s a busy day, you’re running from one event to the next and — surprise! — your period starts. This is a common experience, but one that may be preventable!

After ovulation, your ovaries begin to produce a hormone called progesterone. Progesterone is great for your health and fertility: it maintains the uterine lining, promotes sleep and relaxation, and can even decrease anxiety.

Progesterone levels are only high for a few days during your cycle, though (unless you’re pregnant). They naturally decrease in preparation for your period. So if you know how to identify the signs of decreasing progesterone, you’ll be more confident about knowing when your period may start tomorrow! 

Here are a few of the biggest signs your period may come tomorrow: 

Changes in Appetite or Cravings

Have you ever had a day where you were ready to eat all the carbs? We joke, but there is a relationship between that time right before the body sheds its lining and the need for extra carbs and sugars. 

Research shows that the body can experience a drop in serotonin, a chemical messenger that influences mood, right before the period. To increase the serotonin again, it needs carbs that can quickly be processed into glucose, the body’s main source of energy.

So the body may demand carbs and demand them fast! (Think simple carbs like chocolate ice cream, pasta, or salty potato chips.)

7 signs your period may come tomorrow

To increase serotonin, the body needs carbs quickly.


Suddenly notice your skin isn’t as clear as it normally is? It could be a sign that your period is on its way!

Acne that pops up a week or less before your period starts, and then improves when your period is over, is likely hormonal in cause. That’s because a drop in hormones can cause your glands to produce an oily substance that lubricates the skin, but also (unfortunately) clogs up pores. 

It can be a helpful sign that your period is on its way, but if you’re looking for tips to reduce pre-period acne, try reducing your sugar intake leading up to your period. High-glycemic index foods (like white bread, cereal, desserts) are shown to worsen acne and increase inflammation.


Perhaps the most familiar sign that your period may come tomorrow is seeing a bit of spotting when wiping or on a liner. Spotting is only very light and does not require use of menstrual products larger than a liner.

Progesterone is responsible for maintaining the integrity of the uterine lining (which sheds during a period). Healthy progesterone levels keep the lining thick and healthy until the day you begin your period with a moderate or heavy flow.

But an early decrease in the hormone may allow the lining to start breaking away prematurely, and this is when you’d notice premenstrual spotting. 

7 signs your period may come tomorrow

An early decrease in progesterone may cause a bit of premenstrual spotting.

Mood Swings

Human bodies thrive with healthy hormone levels. Still, hormones go through natural changes, including during the menstrual cycle. Right before your period starts, both estrogen and progesterone naturally decrease in order for the uterine lining to shed. 

When these hormones decrease, it’s common to feel mood swings. You may notice you’re more tearful, especially irritable, or even more likely to feel depressed a day or two before your period starts. 

If these symptoms go away as your period begins, it’s likely they’re due to shifting hormones. If you notice these changes more than a day or two before your new cycle, though, we recommend consulting your doctor. 


It’s common to think of cramping while on your period, but did you know it can begin before your period gets started? 

That’s because the uterus needs to contract in order to shed its lining during a period. Those contractions are what we call cramps, and it may take the uterus a day or two to respond to them.

Each person will have a different experience, but if you notice cramping a day or so before your bleeding begins, this may be a sign your period may start tomorrow!


Do you notice a drop in energy right before your period? 

Your energy level changes throughout your cycle. It’s often at its highest right before ovulation, because of high estrogen levels. Estrogen helps the body do amazing things, like form bone, stimulate brain cells, and increase energy. 

When estrogen decreases after ovulation, progesterone increases, promoting sleep and relaxation, as well as supporting brain function and normalizing blood sugar.

As both hormones drop at the end of your cycle, you may notice that fatigue kicks in and want to grab that extra cup of coffee! 

7 signs your period may come tomorrow

When estrogen and progesterone drop at the end of your cycle, you may experience fatigue.

Breast Tenderness

Studies have shown that breasts are sensitive to the hormone shifts throughout a menstrual cycle, and can change with each phase. When estrogen levels rise before ovulation, the breast ducts increase. When progesterone levels rise after ovulation, breast lobules (also known as milk glands) increase.

You can expect breasts to experience change (and tenderness) with any drastic hormonal shifts, which means that, in addition to it being a sign of your period, breast tenderness may also be a symptom of an early pregnancy (with rising progesterone levels). 

If you are trying to get pregnant and your period does not start, it may be time to take a pregnancy test

Premenstrual Syndrome

If you experience all of these signs, or experience some of them intensely, you may have premenstrual syndrome (PMS). PMS occurs when several interfering symptoms occur during the last half of a menstrual cycle and improve during menstruation.

PMS affects approximately 5% of the menstruating population. Keep note of your symptoms, when they begin, their severity, and how long they last. Talk with your doctor about your experience and possible treatments for improvement. 

Next time you notice any of these symptoms, remember that they may be a sign that your period could start tomorrow: Grab your favorite menstrual product, and feel confident knowing youll be ready no matter what comes your way!

Trying to conceive? You may be interested in how these symptoms could relate to early pregnancy: 

Have questions? Email us!