There are times you get blue. It can slow you down, make you think. Can you look at feeling blue as a gift, just for those reasons? You can go so fast and so much is vying for your attention that you miss important signs that it is time to slow down.
If you feel blue, look at it as an indicator that something is out of alignment. It is a sort of blue flag, instead of red flag, that is waving in front of you.
I have started practicing this and find it useful. If I create time for self-examination, I can usually find the source of my blue feelings quickly. Then I deal with them. Many times, I realize that if I had not acknowledged the blue flag I was heading for a crash.
You can resurrect yourself from feeling blue and be better off for it. Keep an eye out for those blue flags.