What I meant with "System Preferences > Network" is the network preference pane, the one you obviously deleted your network from.
To get your network back, either click the AirPort / WiFi icon in the Menu Bar and select your network to connect to, or click the little "+" icon in System Preferences > Network and add your network from the dropdown list after "Network Name:", which is visible after you pressed the "Create" button.
The password will be still stored in Keychain Access (located in Applications / Utilities or found via Spotlight). Thus your Mac should automatically connect to that network of yours without asking for a password.
But you can use Keychain Access to find out your WiFi network password via clicking on the network name in there and click the "Show password" checkbox.