I used to love sleeping so much, but now I struggle to get a full eight hours of sleep.
Insomnia
Insomnia, also known as sleeplessness, is a sleep disorder in which people have trouble sleeping. They may have difficulty falling asleep, or staying asleep as long as desired. Insomnia is typically followed by daytime sleepiness, low energy, irritability, and a depressed mood. It may result in an increased risk of motor vehicle collisions, as well as problems focusing and learning. Insomnia can be short term, lasting for days or weeks, or long term, lasting more than a month 
Insomnia can occur independently or
, during the Soviet years, but now I can say that I caused damage to my health because of that flight.” On 31 May 2013, NASA scientists reported that a possible manned mission to Mars may involve a great radiation risk based on the amount of energetic particle radiation detected by the RAD on the Mars Science Laboratory while traveling from the Earth to Mars in 2011–2012.
Effects of space-travel Sleep disorders.
Fifty percent of space shuttle astronauts take sleeping pills and still get two hours or less of sleep.