Extremely anxious or distressed.
sick at heart
Despairing, distressed, or anxious.
sick to the back teeth
Extremely annoyed, fed up, tired (of or with something).
sick and tired
Bored to the point of weariness.
sick puppy
A person who is sick (mentally disturbed) in a morbid or gruesome way.
sick man
A weak member of a peer group, especially the weakest.
sick list
A list of people who are ill.