@Louis1847 you can't get the dates back. You have potentially ruined someones trip through your negligence so Airbnb fine you and block your listing as punishment. Anyway if you didn't have time to clean before you cancelled I guess you'll have plenty now.
@Louis1847 Unfortunately, there are many penalties for cancelling a booking, as explained below,
As a new host, do spend some time in the help center, reading articles to familiarize yourself with how things work, so you can avoid pitfalls going forward. Best of luck!