Heart in your mouth
To feel very anxious or nervous.

Cry over spilled milk
To waste time worrying about things that have already happened and cannot be changed.

Break someone's heart
To cause someone emotional pain, especially in a romantic context.

On cloud nine
To be extremely happy.

Burning with desire
To have a strong desire or passion for something.

A roller coaster of emotions
Experiencing many different feelings, especially excitement and disappointment.

Bite the bullet
To face a difficult situation with courage.

Feeling blue
To feel sad or depressed.

Walking on air
To feel very happy or elated.

In the same boat
To be in the same difficult situation as someone else.

Jumping for joy
To be extremely happy.

A heart of stone
To be emotionally cold and unfeeling.

Get cold feet
To become too nervous or afraid to do something.

Keep a stiff upper lip
To remain calm and composed in difficult situations.

Bursting with pride
To feel very proud of someone or something.

Throw in the towel
To give up or admit defeat.

Head over heels in love
To be very much in love.

In high spirits
To be very cheerful or happy.

Cold as ice
To be very unemotional or unfeeling.

Heart skips a beat
To feel a sudden rush of excitement or fear.