try refreshing your cache, do you know how to change your dev mode to true?  if so then do that and hit f5 on the site a couple of times. 

I would recommend using the extreme cache plugin but you cant get to your plugins you said so use the dev mode method and see what happens. 

Also after you do the dev mode refresh try loading the site in another browser, some browsers love to hang on to cache for dear life so try another browser.

log into your Cpanel and open up  ow_includes/config.php

down below you will see this code

    /**
    * Make changes in this block if you want to enable DEV mode and DEBUG mode
    */

    define('OW_DEBUG_MODE', false);
    define('OW_DEV_MODE', false);
    define('OW_PROFILER_ENABLE', false);
}

now on this line

define('OW_DEV_MODE', true);   change the false to true like this

then save the file, open your site in a browser and hit F5 a few times maybe even on different pages just to be sure. 

Then try your admin area again..  If it has resolved itself and your back in business then change that dev mode back to false, save the file and your done.

Im getting good at this Aliia, first thing i always say is refresh your cache, it fixes 70 percent of the issues.. lol..  

Next ill be saying would you like fries with that and by the way refresh your cache lol... :)

Thanks Aliia.