Some strange warnings on my wordpress website

My website – https://www.apextutor.co.in
I am getting these errors –

Warning: include_once(/home/bhavicmehta/public_html/wp-content/plugins/wp-super-cache/wp-cache-phase1.php): failed to open stream: No such file or directory in /home/bhavicmehta/public_html/wp-content/advanced-cache.php on line 20

Warning: include_once(): Failed opening ‘/home/bhavicmehta/public_html/wp-content/plugins/wp-super-cache/wp-cache-phase1.php’ for inclusion (include_path=’.:/usr/local/lib/php’) in /home/bhavicmehta/public_html/wp-content/advanced-cache.php on line 20

Warning: Cannot modify header information – headers already sent by (output started at /home/bhavicmehta/public_html/wp-content/advanced-cache.php:20) in /home/bhavicmehta/public_html/wp-content/plugins/planso-forms/libs/wp-session-manager/class-wp-session.php on line 124

Notice: The called constructor method for WP_Widget in WPAC_Nav_Menu_Widget is deprecated since version 4.3.0! Use
__construct()
instead. in /home/bhavicmehta/public_html/wp-includes/functions.php on line 3718

You can also open the website to see the warnings.

Also , I am not able to access my wordpress admin panel too.

My website got over-loaded last month. Then I deleted one plugin ( I think Wp-cache) from Cpanel. Since then these warnings are coming.

Thanking You , in advance.