Do you have the paperwork? Do you even know what to do?
Some friends from Canada have setup a service where they will handle most of the heavy lifting for you: I’M A MRS. For a small fee, they will provide you with a package containing all government forms, including forms for passport, SSN, voter registration, driver’s license, and more. For a few dollars more, you’ll also be able to access information that would cover many of your financial contacts: retail credit cards, utilities, insurance, etc.
While this service currently only services Canada, they are expecting to expand into the US soon (if they haven’t done so already by the time you read this).