Q: Can I restore my Calendar after deleting from Icloud

You can try restoring your last backup, however it isn't clear from Apple's documentation that the backup will include your calendar.

Actually I just did it and I used a post from randers4 from Dec 1, 2013 and it worked. I am trying to find that post now to reply to it. It involves unplugging your internet during the restore process. I had deleted two calendars from the iCloud and that removed them from every shared device we had using the same iCloud username. I restored (actually from iTunes as my iCloud had not backed up). It worked great and we now have our calendars back and working.

You may be referring to the process outlined in this user tip for contacts: Recovering deleted iCloud contacts from an iCloud backup.  This works for iCloud calendars too; just substitute calendars for contacts.