Both my kids are away at college too! They were home for 3 weeks for Christmas break and ZoE loved it...she got loved on and walked ALOT. They both left Saturday to return to respective universities and ZoE has been depressed ever since. She keeps going to their rooms and whining. It's always like this when they leave, but usually a few days later she's fine. She seems to know that even though other people come & go...my kids, friends, mum & dad, etc....that I always return. I'm sure Charlie realizes this about you too...and you're his anchor...his security...and as long as you're there, he'll be fine