Earlier today, Groupon India was hacked too, however, it is not known as to who was behind the hack. As a user, it is definitely difficult to find out if your account has been compromised or not. However, a new website called "Should I change My Password" is allowing users to search the database of leaked accounts to see if your account has been compromised.
All you need to do is to enter the email address for your account and click on the "Check it!" button. It will then search the database that have been released by hackers to the public and see if your email address exists in it.
I would want to further add that regardless of whether your email was leaked or not, update your password immediately. It takes only few minutes and you can easily create strong passwords or use tools to generate strong passwords.