Jede Zelle...

This will make you feel happy, even if you don't know German. Here is my English translation. Sing it to yourself when you're feeling blue. Bonus for the motions.

Every cell in my body's feeling happy
All of my body cells are feeling good
Every cell in my body's feeling happy
All of my body cells are feeling good

Every cell in every place
Every cell is feeling great!
Every cell in every place
Every cell is feeling great!

Repeat as necessary.
(Thank you Matthias)