I wonder what would call someone who seems to be unhappy and a bit sad in informal English? In the state in my question, the person doesn't show tendency in talking to the surrounding people and keeps silent and is quite visible from their appearance (comparing their normal status) that they feel sad or at least not in the mood!
Example:
A) What's wrong with you Paul?! Are you OK?
B) I'm OK mom! (said Paul unhappily.)
A) But I don't think so son! You look a bit..................
I know two similar terms which based on published definitions can be used properly and interchangeably in this sense. I would appreciate it if you could let me know what do you think about them and how do they sound to you here and in general.
a. down in the mouth.
b. blue.