As someone would have mentioned had their reply not been deleted for snark, try using FTP or whatever file management tools your host provided you with and navigate to your wp-content directory and rename plugins to plugins-old.
If it's a plugin that's causing this then that should let you into your WordPress installation.
Once you're in you'll need to look at your plugins-old directory and locate and deleted the problem plugin. Then you can rename plugins-old back to plugins and re-activate your old plugins.