This has only happened to me once (knock on wood it never happens again), but about eight months ago, I went to sign into Gmail as I normally would and it wouldn't let me in . . . just like that. As I entered my password over and over, double-checking CAPS LOCK for the umpteenth time as my heart started to race faster, I immediately started freaking out — yes I was at work, and yes I put my deodorant to work that day! Because all my pictures are on Picasa, docs on Google docs, and email (email!) couldn't be accessed, I feel like my entire life flashed before me.
To see what happened next, and to learn some useful tips if this ever happens to you, just read more.
After four hours of this, I realized that Google could lock me out of my account for a week (as I kept entering my password) so I did a bit of searching and realized I had a secondary email associated with the account — hallelujah old-school Hotmail to the rescue! Google was able to send me a link through my hotmail account so I could reset my password and therefore sign in again. To do this, sign in to Gmail, go to Settings, Accounts, and then Google Account Settings, Change Security Question and you should see an option to add a secondary email address. Well I guess a major freak-out wasn't necessary because the Official Google Blog has addressed this issue, providing some helpful tips and tricks if you can't access your Gmail — like not responding to messages that ask you for your login information or utilizing the account-recovery process.