People that aren't teachers often don't really understand the tiredness that comes at the end of a long semester. It's not that my job is physically demanding, or even especially mentally taxing, it's just that I'm on stage, performing in front of groups of 3-40 people for a lot of hours each week. I always have to be "on," and while I try to minimize my teacher talking time because I'm all about the student-centered classroom, it's not like I sit at the front of the class inactively. And....it's tiring. And, I'm always happy when vacation rolls around because I can breathe, and rest, and relax.
Here are some tips for how to get refreshed before the new semester starts:
1. It's quite tempting to do overtime in vacations to make more money. You don't need to resist this urge completely, but a happy balance is best. Work a bit, and rest a bit. I'll usually work intensively at a camp for 2-3 weeks during my 10 week vacation, or I'll try to work 8-12 hours/week for most of the vacation period.
2. Go somewhere. Even a trip somewhere in Korea is helpful. I generally try to leave Korea and go somewhere fabulous in Asia. It reminds me of my happy life here.
3. Try not to get too burnt out during the semester. Boundaries are extremely helpful.
4. Finish your grading as soon as possible. Don't let that stuff linger on for longer than necessary.
5. Schedule an intense planning session of 1-5 days (depending on courses taught, etc), rather than doing it gradually over the vacation. If you do this, you'll always be working.