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If you only had your emails stored online, inside gmail. And you didnt use an email program such as outlook 2010, Thunderbird, mac mail, etc
Then there is only one way in which you can attempt to recover your deleted emails.
Read over this page, and follow the steps listed
If you cant find them by checking the trash folder. Then you will have to follow the second set of steps to secure your account and then file the report for missing messages. Once you click the button to file a report, fill out all the info it asks for and gmail will attempt to find the missing messages.
If you get stuck or run into any issues let me know. And good luck!
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