Hello @Dawn379
There are so many posts here on the CC everyday, several times a day where hosts express how much they need this function brought back as it was so useful.
Make sure you use the Feedback button to let Airbnb know of your frustration and the only way currently to continue adding notes to our calendars is if you switch on the Professional Tools that Airbnb offer to all hosts now, even those with just one listing.
I use these and can still add notes on my calendar - even on blocked days. Here is a guide that was made by @Joan2709 which will walk you through their different uses.
https://community.withairbnb.com/t5/Host-guides/GUIDE-Use-Pro-Tools-to-Set-Calendar-Custom-Pricing-a...