Low mood after your period: why it happens

Estrogen and progesterone are both at their lowest point of the cycle as your period ends. Your body hasn't started building back up for the next cycle yet, so the hormones that usually lift mood are still near the floor.

A 2021 systematic review of hormone studies in women with mood disorders found that PMDD was linked to lower estradiol levels in the luteal (second) half of the cycle [2], though most research points to PMDD being a different reaction to normal hormone changes rather than abnormal levels (Schmidt et al., 1998; Dubey et al., 2017).

That points to some brains reacting more to where estrogen sits, and how it moves, than others do. Scientists haven't studied this directly, but a similar sensitivity to hormone shifts may carry into the first days after bleeding stops, even though the recognized PMS and PMDD window is the week before your period.

A few things can add to a low feeling right after your period:

• Hormones still sitting at their lowest point, before estrogen climbs for the next cycle
• Blood loss and the fatigue that comes with it, which flattens mood on its own
• Leftover PMS or PMDD symptoms that haven't fully cleared yet
• An existing mood condition that worsens before your period and hasn't settled by the time it ends

None of these make the sadness less real. They're reasons it's showing up now, not proof it doesn't matter.

A day or two of feeling flat or low once your period ends is common. A 1991 daily-ratings study of 30 regularly cycling women found mood measures shifted across the whole cycle, not only in the days right before bleeding, with a recognizable dysphoric-mood pattern showing up for many women on a cyclic basis [1].

Common doesn't mean it should be ignored. If the low feeling is heavier than a passing flat day, or it doesn't match what's actually going on in your life, treat that as useful information, not something to push through.

Sadness before your period and sadness during your period tend to get more attention, since they sit closer to the classic PMS window. The days right after bleeding stops can carry a quieter version of the same dip, and it's easy to miss because you expect to feel better once your period is over, not still low.

Paying attention to where the low feeling sits in your cycle, rather than just that it happened, makes the pattern easier to plan around the next time it shows up.

An ordinary post-period dip usually lifts within a day or two, as estrogen starts climbing again in the early days of the next cycle.

It's likely something else if:

• The low mood was already there before your period, not just after
• It doesn't ease even once your period is fully over
• You've noticed the same pattern most months, not just this one

A 2021 review of premenstrual exacerbation (PME) found that around 60% of women with an existing mood disorder report it worsening before their period, and that PME tends to predict a harder overall course of illness, not just a one-time flare [3].

Unlike PMDD, which is expected to ease within a few days of bleeding starting and stay minimal the week after, PME symptoms carry over because the underlying condition is there all month, not only premenstrually.

A broader comorbidity review found that mood disorders and PMDD or PMS overlap often, which is one reason low mood after your period deserves its own look rather than an automatic PMS label [4].

PMS, PMDD, and PME follow different timing, and knowing which one fits matters for what helps. Here's how low mood after your period lines up with each pattern, or doesn't.

If the sadness after your period keeps showing up, and it lasts longer than the first couple of days afterward, PMDD sadness and sadness in the luteal phase cover the other ends of the same cycle and are worth reading next. Neither page will tell you which pattern fits on its own. Two months of daily notes will.

Right now, the aim is to get through today, not to solve the whole pattern.

If you want to see whether this dip lines up with your usual cycle, the PMS calculator can estimate your window from your last few cycles, so you know whether a low day after your period is part of your normal pattern or something new.

Niyora is a PMS and PMDD support app. If you want somewhere to put a low day before you decide what to do with it, Niyora's Moon lets you write down what happened, see it from another angle, and calm down before you respond to anyone or anything.

None of this fixes the hormone dip on its own. It just gives the next hour somewhere to go.

That record is what lets a doctor tell PMS, PMDD, and PME apart, instead of guessing from one cycle.

Treatment depends on what's actually going on, and a doctor decides what fits your pattern. Guidelines point to a few options:

• SSRIs, sometimes taken only in the days before your period
• Certain hormonal contraceptives
• CBT (cognitive behavioral therapy)

If an existing mood condition is getting worse before your period and still present once it ends, that's worth flagging to a doctor on its own. They decide what treatment fits, rather than you guessing at the order. A doctor can also rule out other causes if the pattern doesn't quite fit PMS, PMDD, or PME.

Start with what is PMS if you want the fuller picture before your appointment.