(CNN)"What day is it, again?"
It's become a common refrain during the coronavirus pandemic, a reflection of both how all of the days seem to blur together and how lately, we find ourselves forgetting even the simplest of details.
Our internal clocks are shot. Tuesdays are Thursdays are Wednesdays are Sundays. There are no weekdays, or weekends. There is only yesterday, today and tomorrow.
Along with these feelings of disorientation, it may seem like it's getting harder to concentrate and taking longer to complete tasks, as if our brains are just working more slowly.
If it feels like your brain is turning into mush, you're not alone. Experts say it all has to do with how the pandemic is affecting our cognitive health -- meaning, our ability to clearly think, learn and remember.
"It is a perfect storm between changes in environment, loss of social anchors and increases in cognitive stress," said Elissa Epel, a professor of psychiatry at the University of California, San Francisco. "And then on top of that, most of us are not getting the quality sleep that we used to."
Here's what's going on, and what we can do about it.
Our usual routines are gone
Much like our bodies depend on environmental cues like sunlight to regulate our circadian rhythms, they also rely on physical and social cues, explains Epel.
Those cues include routines like morning and evening commutes, set mealtimes or weekly religious services that help us keep track of what day it is.
For those confined to our homes, those routines have largely disappeared. Days have lost their usual structure, meaning once-clear boundaries are now blurred.