There are no other Gmail accounts that have your account name with the dots in them, and no one else has access to your mail. There might, however, be some confused people out there who are giving out their email address incorrectly, leading people or companies to send email intended for those people to your Gmail account. Probably the only thing you can do is reply to ones that look like the sender might know the intended recipient well enough to have other ways of contacting that person in hopes of them fixing their problem.
If you would like to verify it, try signing into the “other” account with your password. It will work--and you will find yourself in your own account.