Function.php Error

Hi,

I was just working on adding a new user to my site, when suddenly this message appeared:

Warning: Cannot modify header information – headers already sent by (output started at /home3/unotaku/public_html/wp-content/themes/colormag/functions.php:152) in /home3/unotaku/public_html/wp-login.php on line 403

I can’t do anything anymore, not even go to my dashboard.

I don’t know what to do, please help!

Thank you!