You get through the hard conversation, the big family dinner, or the wedding, and the next morning you wake up foggy, flat, and wiped out. Nothing new happened, but you are still having an emotional hangover.

On this week’s podcast, my daughter Dominique and I talk about why this happens and what to do about it. Dominique remembers spending the best day of her life at a theme park as a kid, then coming home sad and feeling down the next day, so she started to dread it.

Your emotions carry over

NYU neuroscientist Lila Davachi and her team found that the brain state from an emotional experience can carry over for 20 to 30 minutes and affect how people take in whatever comes next.

I see this all the time. A small misunderstanding with my husband or a worrying moment in our business can spread through my whole day if I don’t deal with it. Last week I caught myself saying, “This has been such a hard day.” Then I realized I’d never processed something from that morning.

Good days can drain you too

A great day takes a lot of energy. You pay such intense attention that everything feels bigger, and your mind and body build strong networks around it. The next day, you’re rebuilding that energy, so you feel flat.

A study from Finnish researchers Sointu Leikas and Ville-Juhani Ilmarinen found that being sociable lifted people’s mood in the moment but was linked to more tiredness about three hours later, for introverts and extroverts alike. The tiredness was small and short, and the mood boost was worth it. So keep seeing your people, and plan a slow next day.

Holding it together costs you

Smiling when you’re hurt or staying composed when you’re angry takes real mental effort. Stanford psychologist James Gross’s research on hiding your feelings shows how costly it is.

People-pleasing does the same thing. Over-apologizing, smoothing things over by text, and saying yes to the next invitation to prove everything’s fine leave you exhausted. A kind, honest boundary costs far less.

What to do with it

In the moment, observe the feeling without getting sucked into it. Take a few deep breaths, then talk yourself through what happened and what you’ll do next. If the same person or situation leaves you drained again and again, watch for the pattern. Something underneath it hasn’t been processed yet, and the Neurocycle can help you work through it.