Campsick

The opposite of homesick (or home-lonely; medically, you're not actually ill). Intense longing to be back at summer camp. Afflicted persons may show a variety of symptoms, including melancholy, reminiscence, and attempts to incorporate camp culture, routine, and lingo into "real world" life.

The only known cure for campsickness is to send the afflicted person back to camp. Otherwise, be patient with them. Try to distract them without making them feel as though you don't care about how they feel. Listen to their camp stories, even though you've likely heard them more times than you care to. If possible, try to incorporate their favourite camp customs into the "real world". Encourage contact with other "camp people", because they will share experiences and alleviate the feeling of being alone.

After working full-time at summer camp, many counselors missed it so much they became campsick. Most of their friends at school and work did not understand, and aggravated the feeling.