Also have the blues:
to feel blue - to feel sad and depressed.
"I'm feeling blue because I haven't had any mail except bills for a long, long time."
"After seeing the old house in such bad shape, I had the blues for weeks"
The noun blues, meaning "low spirits," was first recorded in 1741 and may come from blue devil, a 17th-century term for a baleful demon, or from the adjective blue meaning "sad," a usage first recorded in Chaucer's Complaint of Mars (c. 1385). The idiom may have been reinforced by the notion that anxiety produces a livid skin color.
Colour psychology says that Blue can create feelings of
sadness or aloofness. Colour Blue can also
lower the pulse rate and body temperature.
The blues, (used with a plural verb
) depressed spirits; despondency; melancholy; depression.
"This rainy spell is giving me the blues."
Blue Monday:
a Monday regarded as a depressing workday in contrast to the pleasant relaxation of the weekend.