The hard drive where I stored the private key (needed for uploading to the Chrome Web Store) got erased. Is my only option to delete the extension from the Web Store and recreate it? Any tips for salvaging what I have?
Yes, I'm aware it was stupid not to keep a backup of my key.
The only moment when including a key has any effect is the first time you upload your extension to the Chrome Web Store, as that will determine the extension ID. After that, you don't need a private key to update your extension.