@Sora0.....Yes Sora, as the other hosts have said this cancellation will 'haunt' you for a year!
You may possibly have left it too long now to expect help from Airbnb in coming to a solution that would be more in your favour.
You have also no doubt been financially penalised as well for this cancellation!
Host cancellation is something a host should NEVER do! Sora, there are always other ways to find a solution, or to have a guest relocated if you contact Airbnb and work with them. I cannot begin to tell you how many times this exact same question has come up and you, as a 'Superhost' should have been well and truly aware of the penalties imposed on hosts who cancel.
Now, although time is against you, you can contact Airbnb and plead a case for mitigating circumstances for this case. You do have a good record and that may go in your favour. The help team are fair (in most instances) and you don't know unless you try, and it is important for the following reason!
As far as the fall off in bookings since this event, it is doubtful that the loss of superhost in itself would have cost you bookings but, that automated response on your reviews certainly would. Guests do not feel comfortable booking with a host who has a record of cancellation. The automated response is all the time being pushed down in your ratings and will eventually be so far back as to have no effect! Very rarely do guests read all a hosts reviews.
Also, could there be other external influences that are restricting your bookings...has it been a cold summer? Are other hosts in your area experiencing a down turn?
All the best Sora, see how you go with the help team and I hope it all works out for you...cheers.....Rob
