That must be so very difficult for you! But they are coming back soon, a lifetime to you, a blink of the eye for them. Katheryn's right, they'll have loads of stories for you.

To make yourself feel better and let them know how much you missed them, buy or make a card for each of them with daily thoughts. "I saw ____ and thought of you. etc

When they come back, you'll have something to share with them too.