The sluggish, tired feeling you get after your lunch break at work. Often leads to lethargy and a tendency to get little done and/or kill time until the end of the day.
"I was so productive earlier today, but after sitting down for a half-hour and having that burger I'm having wicked break lag."
A temporary disruption of the body's normal biological rhythms after being on break from school. Similar to jetlag but is caused by going back to school after being on break rather than by time zones. A person experiencing breaklag will find that they cannot sleep until very late and cannot wake up on time for classes upon returning to college.
Mina: "...also, why are you still awake?"
Christina: "I either don't sleep or I go to bed past 6am."
Mina: "Breaklag much?"