Log In Issues and warning errors

Have just recently been doing a few things on our site, added wordfence secuirty and added a SSL connection for our shop, but now when I try to log in with my normal user name and password these warnings are displayed at the top of the log in page and then more errors appear once i try to log in (see below the 2 first warnings)

Warning: Cannot modify header information – headers already sent by (output started at /clientdata/apache-www/s/y/sydneylighthouse.com.au/www/wp-content/themes/SL/functions.php:1) in /clientdata/apache-www/s/y/sydneylighthouse.com.au/www/wp-login.php on line 368

Warning: Cannot modify header information – headers already sent by (output started at /clientdata/apache-www/s/y/sydneylighthouse.com.au/www/wp-content/themes/SL/functions.php:1) in /clientdata/apache-www/s/y/sydneylighthouse.com.au/www/wp-login.php on line 380
Sydney Lighthouse

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Warning: Cannot modify header information – headers already sent by (output started at /clientdata/apache-www/s/y/sydneylighthouse.com.au/www/wp-content/themes/SL/functions.php:1) in /clientdata/apache-www/s/y/sydneylighthouse.com.au/www/wp-login.php on line 368

Warning: Cannot modify header information – headers already sent by (output started at /clientdata/apache-www/s/y/sydneylighthouse.com.au/www/wp-content/themes/SL/functions.php:1) in /clientdata/apache-www/s/y/sydneylighthouse.com.au/www/wp-login.php on line 380

Warning: Cannot modify header information – headers already sent by (output started at /clientdata/apache-www/s/y/sydneylighthouse.com.au/www/wp-content/themes/SL/functions.php:1) in /clientdata/apache-www/s/y/sydneylighthouse.com.au/www/wp-includes/pluggable.php on line 680

Warning: Cannot modify header information – headers already sent by (output started at /clientdata/apache-www/s/y/sydneylighthouse.com.au/www/wp-content/themes/SL/functions.php:1) in /clientdata/apache-www/s/y/sydneylighthouse.com.au/www/wp-includes/pluggable.php on line 681

Warning: Cannot modify header information – headers already sent by (output started at /clientdata/apache-www/s/y/sydneylighthouse.com.au/www/wp-content/themes/SL/functions.php:1) in /clientdata/apache-www/s/y/sydneylighthouse.com.au/www/wp-includes/pluggable.php on line 682

Can anyone please help with this?

functions.php

1-2 line
<?php
/*

wp-login.php

368 line
header(‘Content-Type: ‘.get_bloginfo(‘html_type’).’; charset=’.get_bloginfo(‘charset’));
380 line
setcookie(TEST_COOKIE, ‘WP Cookie check’, 0, COOKIEPATH, COOKIE_DOMAIN);

pluggable.php

680-682 lines
setcookie($auth_cookie_name, $auth_cookie, $expire, PLUGINS_COOKIE_PATH, COOKIE_DOMAIN, $secure, true);
setcookie($auth_cookie_name, $auth_cookie, $expire, ADMIN_COOKIE_PATH, COOKIE_DOMAIN, $secure, true);
setcookie(LOGGED_IN_COOKIE, $logged_in_cookie, $expire, COOKIEPATH, COOKIE_DOMAIN, $secure_logged_in_cookie, true);