Momentary Feeling of Purposelessness

I'm at school right now waiting for the next class. Our leadership class dismissed an hour earlier. So I did as I planned visit the bank to make some transactions.

I'm still in this state of "momentary feeling of purposelessness". I don't like the feeling. For one, I'm not smiling. For someone who has been coined to be rarely smile, this one I consciously notice. My prayer: "Lord, restore the joy of my salvation." John Piper in his study of Psalm 51 said it's the lost of that joy in the presence of the Lord followers of the Lord get distracted and do stupid things. How do you bounce back from this feeling? I have gone through worse breakdowns and I could see this is not the max of it.