Your email was probably hacked and they disabled the authenticator. You should have 2 factor authentication on the email too. There's no way that I know of to remove the 7 day limit of the bank PIN, so either your computer was compromised and they've been recording you enter the pin or your pin was saved somewhere in text or very guessable. If it happened to me and I couldn't be bothered to investigate how exactly it happened, I would just wipe all the data from my computer and do a fresh install of the operating system, and make sure the email account was secure. I'd probably also be a bit wary about other devices on the same network potentially being infected.
You should use a different password everywhere and you should use a password manager to keep track of them (because memorizing so many passwords isn't really realistic). I recommend using LastPass. You can use it as a browser extension or portable exe. It syncs the passwords on their server in an encrypted format, so they can't access the password files because they don't have the keys to decrypt. You can have 2FA on the downloads from their server.
Other popular alternatives would be 1Password, Dashlane or KeePass. KeePass is probably the most secure one, but then you run into synchronization issues between different devices. There is a plugin for synchronization but I don't trust that.