Error on admin page

Hello I am getting this error when I try to access the admin

Warning: Cannot modify header information – headers already sent by (output started at /home/jjohnson/public_html/wp/wp-content/themes/branfordmagazine/functions.php:22) in /home/jjohnson/public_html/wp/wp-includes/pluggable.php on line 770

I dont know what is wrong it was working fine on friday and now is not

the site is working fine but not the admin

http://jackiejohnson84.com/wp/

Hope you can help

Thank You

Joaquin Encinas