How do I recover missing calendar events after an iOS update?

Did another update I guess updates are weekly now. Everything on my calendar disappeared. My calendar doesn’t look the same. I can’t get everything back. I tried the sinking. I tried to all that crap nothing worked and I am a small business owner who is probably gonna be completely screwed from this so thanks Apple would be great if I could get all my appointments back in my calendar by today or tomorrow, but that won’t happen

[Re-Titled by Moderator]