A quick visit to the Apple genius bar (or whatever they call it now), might save you a lot of time.
Your calendar events might be really gone, they might not. It depends on "where" your calendar really lived and how it was deleted (or hidden).
Trying not to overwhelm you with options, and sorry if I'm rambling a bit, but ....
- If the calendar events were *only* saved on your phone and you really deleted the calendar, then they're likely gone (ugh).
- If the calendar was on your phone, but also auto-sync'd with your iCloud account, then it might be recoverable (but ... not guaranteed; e.g. if you deleted the calendar and then that empty calendar was copied to the iCloud deleting the backup copy there).
How you "deleted" the calendar makes a difference too. You might have just hidden the calendar from being displayed in the Calendar app. You might have hidden the Calendar app and your data is really fine. Or you might have actually deleted the calendar events from within the calendar app ... the options are more than a few and it's hard to guess what it is that's happened.
Crossing fingers that your calendar is just not getting displayed and isn't really deleted. In the Calendars app, tap "Calendars" at the bottom — sometimes calendars get accidentally unchecked and just look "gone."
Apple really really tries to get you to sign into iCloud when you initialize your phone. And it'll often back up lots of stuff to iCloud without a lot of intervention by you (e.g. pictures, notes, mail, calendar events, etc., etc.).
Depending on how exactly you had your calendar (and phone) configured and how you "deleted" it, the data could be lost or it could just not be getting displayed or it could be in the iCloud waiting for it to be downloaded again to your device or ... probably other options I'm not thinking of right now.
Bottom line:
(1) If you know your iCloud login and password, you could login to icloud.com (with a normal web browser) and see if you can view your calendar that was sync'd with your phone without your noticing. But ... if you're not used to doing this, now might not be the best time to learn to do it. E.g. some of the authentication requirements & prompts can get confusing and the web interface can show you all the stuff in your iCloud account... which might be a bit overwhelming. And frankly I'd be a little worried about accidentally deleting the backup 
(2) If you have an Apple retail store handy, give them a visit. Maybe bring your Mac laptop with you too if you've got one sharing your iCloud account. I think they
Good luck and hope this helps and doesn't just stir up the mud for you.
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