A common method of attack is "phishing" - sending emails that attempt to trick a user into sharing their login credentials. Phishing emails will often warn a user that somebody has tried to access their account, and suggest they change their password immediately.
Somebody just used your password to sign into your account.
IP Address: 112.133.112.021
Location: Romania
Google stopped this sign-in attempt. If you do not recognize the details above, you should change your password immediately.