Sadly, (and I know it must come as a real blow) a blue funk is not a kind of hip indie music genre. It is in fact nothing to do with music.
It's not nice at all.
What a bummer.
A blue funk is what happens when you get really nervous and scared about something in the future (I get them). It puts you in a state of panic.
(This is the point where you wish blue funk was a kind of music which you could use to destress when you are in a blue funk)
Use in Normal SpeechEdit
"I'm not looking foreward to those exams on Friday. I am in such a blue funk I don't know if I'll be able to eat on the day."