The host was correct that you need to contact Airbnb, but you need to do it through your itinerary, @Patty282 . This is just a forum of hosts and guests who cannot help with specifics.
So the first thing to try is to see what pops up when you hit CANCEL on the reservation. There should be something that asks you whether it is COVID-related and prompts to follow after that.
If that is not happening, then you need to call Airbnb. There should be contact information in your itinerary, but if not, google the number for your country or tweet (via Twitter) to AirbnbHelp.
Get well soon!