Check your Gmail / Google account password. Have you recently changed it? If yes, then you will need to re-enter your password on your Android device to get all your Google services back. As soon as you change your Google account password, your device gets a notification to enter the new password. Do it or your Google Play Store or any other Google service will not sync or work properly. Which can cause all kinds of havoc.
You may not be able to do this on a phone. Try logging into your google account from a computer and see if it will let you log in. If not, it may allow you to change the password, which may gain you access to this on the phone.