I received a message saying I must change my iCloud Keychain pass code due to changes in the server. Is this correct? Or is it a scam?

It is a phishing attempt to steal your personal info. Do not respond, do not divulge any personal or financial information.

Dang! And if I already did before thinking it might be a scam, what can I do about at this point? I did just reset my password again after realizing it might be a scam, but is that sufficient and is there anything else I should look into to see if any damage was already done? Thanks.