Cache issues

I started advertising my website on facebook.. And the traffic increased from 21 to 1300 within 5 hours. My website went off completely...I was getting 500 internal error... After some time, l started getting errors...I spoke to my host and they said the issue has to do with the Joomla Cache..The main system configuration cache time is 15....

Can l give u my backend..For you to check on the caching on the site for me..Whether something is wrong..

Please attach here screen with your cache configuration, and make sure that you use File as a session handler (not database). Secondly please check your server disk space and size of /cache directory (maybe old files are not delete automatically).

Where can l find "File as a session". I have a lot of disk space on my server..About 45 GB remaining... Where can l check the size of Cache directory..

Also, some of the images l place at the editor shows once.. After reload it doesn't show again..When l clear the caches it shows up...

Thanks

Where can l find "File as a session". I have a lot of disk space on my server..About 45 GB remaining... Where can l check the size of Cache directory..

Also, some of the images l place at the editor (using custom HTML) shows once.. After reload it doesn't show again..When l clear the caches it shows up...

Cache directory size in size of root/cache folder, to check the size you need to login via ftp.

Cache handler you can find under Joomla settings, in the same place where you set time limit for cache. If you can't find it please attach here screen with your cache configuration in Joomla Global Settings.