sick at heart
Grieving, very disappointed, dejected, as in We were sick at heart when we learned of her predicament. This idiom, which transfers heart disease to unhappiness, was first recorded in 1581.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.