There have been a lot of data breaches with other software and services. if you use the same password and/or e-mailaddress also on Evernote, you´re - excuse my words - fucked. It doesn´t mean Evernote has been breached, it is just very likely that your password and e-mailaddress are also used somewhere else and that that service was hacked.
Check https://haveibeenpwned.com/ to see which services that you use have been breached and in which ones your details became known. Changing the Evernote password is not enough, you also have to change the password of your e-mail, since a) most people use the same password for that and b) password reset mails are being send to that address, which isn´t wise if someone also has access to your mail and can read where you updated your passwords.
This site uses lists of leaked accounts that are being shared between hackers.
So, change passwords everwhere, using the password generator of your password manager.Use long and unique ones everywhere. Setup two-factor authencation where you can.