your heart isn't in something

(one's) heart isn't in it

One is not emotionally invested in something. I used to love running, but my heart just isn't in it anymore—that's why I quit the track team this year. I can tell by the way you wrote this that your heart wasn't in it. Is something distracting you?
See also: heart
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

your heart isn't in something

If your heart isn't in something you are doing, you are not enthusiastic about it. Note: The heart is traditionally regarded as the centre of the emotions. Playing was no longer fun. I lost my competitiveness and my heart wasn't in it. She was a successful teacher, popular with her pupils and her colleagues, but her heart wasn't in it.
See also: heart, something
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012
See also: