@Nancy46 I think everyone is experiencing some slowdowns. I compared my March listing views to the same time last year and was short by about 40 views. Fortunately I still got reservation requests so the actual number of reservations is the same.
Cancelling a guest's reservation has huge consequences, one of which is the automated cancellation review . It's possible that guests looking at your listing see this and decide not to book.
As for asking a guest to cancel, don't know where you got that. It was your mistake, not the guest's and you should never ask a guest to cancel when they did nothing wrong. You should know that when a guest cancels, they are not refunded the Airbnb service fee so that would have added insult to injury so to speak. When this happens, guests complain bitterly to Airbnb (as they should) and that's not good for you since Airbnb asks them for their reservation number.
Super Host status does improve search rankings so the loss of Super Host status may have caused your listing to slip in the search results.
All you can do is keep giving great service and over time the consequences of the cancellation will go away. I'm sure you will recover!