Hello CalendarGone,
Thanks for posting in the Apple Support Communities.
It sounds like your calendar events are missing on all of your Apple devices, right?
If we have that correct, let's see if these may have been accidentally deleted from iCloud. Since iCloud can sync your calendar events, this will be the first step to check on what's occurring. Follow along with the steps below for assistance with checking this, and you can find more details in this resource: If you accidentally deleted your calendars, bookmarks, or contacts from iCloud - Apple Support
Restore your calendars from an earlier version
Several things happen when you restore an earlier version of your calendars.
• Your sharing settings get erased. You can share the calendars again, or you can ask the owner to share them again.
• iCloud cancels and recreates all of your upcoming, scheduled events, then resends the invitations for you.
To restore your missing calendars:
1. Sign in to iCloud.com.
2. Scroll down to the bottom of the window, then select Data Recovery.
3. Select Restore Calendars.
4. Select Restore next to the date before you deleted the content.
5. Select Restore again to confirm. After the restore completes, you get a notification on iCloud.com and an email at the address on file with your Apple ID.
If you're still unable to see your calendar events, do you know if you may have removed an email account that you no longer use on your devices? If so, we may need to check if that email account had the calendar events stored. The following resource includes steps to check for multiple calendar accounts on your iPhone, as well as instruction on how to add an account if one was removed. Check out the steps, here: Set up multiple calendars on iPhone - Apple Support
Let us know if this helps to clear up what's happening. If not, confirm where you had the calendar events set to sync so we have a better understanding of this. Feel free to include any additional helpful information to provide us with more details to work with.
Have a great day!