how to recover mail

dear sir,
I have deleted my important mail from gmail and i have seen that mail in trash but i forget to make recover it from trash. After few days i used to recover it but that mail was not in trash.I just got the message was that deleted mail from the account was only 10 days in trash.I was shocked and i cant do anything to recover. could you help me recover it. if anything possible mean please do reply.

thank you,