If you deleted it from your phone, just enter it again - as an existing account. It should still load emails from the past 2 weeks.
If you somehow deleted it from Google (use a browser and go to GMail to find out - if there's no account there, you deleted it fro Google), you'll have to contact Google and ask for assistance to bring it back. (I'm not guaranteeing that they can, but if it's possible, they're the only ones who can.)