(your) heart sinks

you become discouraged or disappointed.

My heart sank when I opened the letter and realized I had not been accepted into graduate school.

• call off something
• call off the dogs
• call on
• call on someone
• call own
• call someone names
• call someone's bluff
• call someone to heel
• call something into question
• call the shots
• call the tune
• call to account
• call to heel
• call up
• call up someone
• call up something
• call your bluff
• call your own
• calm before the storm
• camp follower
• camp out
• can count on the fingers of one hand
• can count something on the fingers of one hand
• can-do
• can do something on ear