What does the phrase, "i have the blues" mean to you?

Different words and different phrases have different meanings to different people. my wife, in our younger years, once told me, “don’t bother me today, i have the blues”. being much younger, i did not understand exactly what she meant. today, i am sometimes still confused, when i am again told this by her. so, what does the phrase, “i have the blues” mean to you. this can be a question for a man or a woman.