Can't login to CP

I have looked around before posting and none of the other answers helped my problem. So, here I am posting on this forum.

When I go to my admin.php and enter correct username and password, there’s a blank page with a loading and after 2-3 minutes, this errors show up :

A Database Error Occurred Error Number: 2006 MySQL server has gone away SELECT module_id FROM exp_modules WHERE module_name = ‘Structure’ Filename: third_party/structure/acc.structure.php Line Number: 38

This is what I tried so far : - Repair&Optimize; exp_modules table - I cleared my cache folder - I put $config[‘cookie_prefix’] = ‘my_site_name’; in /system/expressionengine/config/config.php - I changed $config[‘allow_extensions’] = ‘y’; to $config[‘allow_extensions’] = ‘n’;

I am using ExpressionEngine2 version 2.2.2 with structure module version 3.0.3 And this is the top of my config.php file :

$config[‘app_version’] = ‘222’; $config[‘install_lock’] = “”; $config[‘license_number’] = “****-****-****-****”; $config[‘debug’] = ‘1’; $config[‘cp_url’] = ‘http://www.my_site_name.com/system/admin.php’; $config[‘doc_url’] = “http://expressionengine.com/user_guide/”; $config[‘is_system_on’] = “y”; $config[‘allow_extensions’] = ‘y’; $config[‘site_label’] = ‘my_site_name’;

I really don’t know what to do now so I’m asking your help guys. Thanks.