If you tend to fall asleep as soon as your head hits the pillow, you might chalk it up to being a good sleeper—but it might not be all good! Falling asleep quickly often signals severe sleep deprivation, and possibly even a sleep disorder. Other signs of sleep deprivation include an unusually high degree of impulsivity, forgetfulness, being unusually hungry, and difficulty concentrating.

MORE: 10 Surprising Signs You Are Sleep-Deprived