Could you describe “my site crashed”?
If there is ever an issue when upgrading a plugin, any plugin, generally, all you need to do is delete the plugin’s folder from within the
../wp-content/plugins folder. For example, you would just delete this folder to remove Connections:
I suspect you ran out of memory assigned to PHP. This actually could happen at any point with any plugin depending on how much memory overhead they require to run when added to the memory required by the total sum of the memory in use by WordPress, the theme and the plugins.
To help identify if this is the issue, can you attach screen captures of the System widget on the Connections : Dashboard admin page?