We have been having some massive "Separation Anxiety" issues with Kiera as of late until we stumbled across this book: Mama Always Comes Home.

Description:

Mama Bird and Mama Cat and even teensy-weensy Mama Mole must leave their little ones from time to time; but in the end, mamas always come home.

Karma Wilson's reassuring text, paired with Brooke Dyer's colorful and comforting mother-child illustrations, shows that -- rain or shine, in a tree or in the sea -- mamas everywhere find their way home with cozy hugs and lots of love, because Mama Always Comes Home.

Excellent  book and I highly recommend it if you have separation anxiety issues with your little ones. It's worked for us.