If you’re having trouble concentrating or are drowsy after a poor night’s sleep, try taking an afternoon nap! A nap as short as 5 minutes can help improve your focus and make you feel refreshed. But try to limit your nap length to 45 minutes or less–anything longer than that will leave you drowsy.
Also, if it’s already late in the afternoon, try to wait until your usual bedtime to sleep. A nap too late in the day will make it hard to fall asleep and will continue to disrupt your sleep cycle.