It broke through late last night that as many as 5 million Gmail passwords were compromised, and as a result you must go back and change your passwords, once again. In the wake of Heartbleed and several other cases where passwords were compromised and the debacle of iCloud recently, your password must be really herculian to stand the test of these events. But the sad part is, eventually we have all ran out of the words and symbol combinations that we can use passwords. unless you use a service like 1Password, coming up with new password in the wake of every such disaster is impossible.
The password list, was apparently leaked out on the Russian BitCoin forum, but since has been taken down. But obviously, this means, there is somebody out there other than you who has access to your Gmail password.
Instead of sweating about it, you can check whether your password was one of the leaked ones, by going over to the log here and inputting your Gmail ID. The site will let you know if you are one of the unfortunate 5 million people whose passwords were taken for a ride and therefore can change it. In case it is not, we do recommend you change the password and just to be on the safe side, you can change the passwords and should make it a habit of doing so every month now given how insecure everything on the web is.