Why are my changes gone after a cancelled git commit and how do I recover them?

Here's what I did:

1. Coded 8 hours worth of changes.
2. git status displays all my changes.
3. git add -A
4. git commit -m "Foo". A pre-commit git hook fires with husky and lint-staged.
5. I remember that there's a TypeScript typing error I failed to fix, so I press Ctrl+C to cancel.
6. Absentmindedly, I run git commit -m "Foo" again and immediately cancel.
7. Changes are gone! The files are reverted, git status is clean, git log and git reflog do not show a new commit.

Why did my changes get reverted? How do I recover them?