To be or feel under the weather
To not feel well.
To be as sick as a dog
To be very sick.
To hold someone's horses
To be patient and wait.
To be/feel down in the dumps
To be or feel sad or depressed.
To be Greek to somebody
To be impossible to understand.
To get a slap on the wrist
Give someone a mild punishment.
To be a loose cannon
To be unpredictable.
To pull someone's leg
To be just joking.
To be tickled pink
To be very happy.
Till the cows come home
For a very long time.
Close, but no cigar
You were close, but you didn't make it.
Hands down
Without competition.
Rise and shine
Wake up and be happy!
To cost an arm and a leg
To be very expensive.
To keep someone's chin up
To be happy.
To be in the same boat
To be in the same position or unpleasant situation as other people.