Answer: Sleep debt.
Explanation: The lengthy sleep time few days after Jeremy's semester ended suggests that he ended the semester with a sleep debt. A sleep debt most often times refered to as sleep deficit is the total amount of sleep time lost i.e observed sleep time not been sufficient (sleep need). It might be due to personal deprivation (restrictions) or medical issue like insomnia, not getting back those sleep time lost can cause issues like; fatigue, headache, lack of concentration, bad mood etc. It usually takes four days or more to pay back sleep deficit because it's a gradual process.
