Parse error, syntax error, fatal error after i put in a php code

Hi, yesterday i installed the plug in ‘my custom functions’ on my wordpress site and i tried to add a php code to change the size of my thumbnail pictures. The code i put in did something to my site and now it just displays a white error screen that says this:

Parse error: syntax error, unexpected end of file in /home3/chefasht/public_html/wp-content/plugins/my-custom-functions/my-custom-functions.php(216) : eval()’d code on line 1

Fatal error: Uncaught Error: Call to undefined function is_user_logged_in() in /home3/chefasht/public_html/wp-content/mu-plugins/endurance-page-cache.php:235 Stack trace: #0 /home3/chefasht/public_html/wp-content/mu-plugins/endurance-page-cache.php(272): Endurance_Page_Cache->is_cachable() #1 /home3/chefasht/public_html/wp-includes/class-wp-hook.php(298): Endurance_Page_Cache->finish(”) #2 /home3/chefasht/public_html/wp-includes/class-wp-hook.php(323): WP_Hook->apply_filters(NULL, Array) #3 /home3/chefasht/public_html/wp-includes/plugin.php(453): WP_Hook->do_action(Array) #4 /home3/chefasht/public_html/wp-includes/load.php(677): do_action(‘shutdown’) #5 [internal function]: shutdown_action_hook() #6 {main} thrown in /home3/chefasht/public_html/wp-content/mu-plugins/endurance-page-cache.php on line 235

obviously i’ve stuffed up the main settings when i put in the php code, ive disabled and deleted the plug in but im still having the error. I’m not sure how to fix it. I am a total novice and new to wordpress since a week ago.