HOW TO UNDO UNEXPECTEDLY SENDED MAIL IN GMAIL?

If you make a regret sending a message, you can undo the action by enabling "Undo send." This setting gives you the option to take back a message you just sent.

To enable Undo Send:

1. Click the gear in the top right (settings icon as we knew)
2. Select Settings.
3. Scroll down to "Undo Send" and click Enable.
4. Set the cancellation time period ((time you have to decide if you want to unsend an email).
5. Click Save Changes at the bottom of the page.

If you had Undo Send turned on in Gmail Labs, your Undo Send setting will be on by default.

Note: To give you time to undo, Gmail delays sending the message for a 5 to 30 seconds. So if you don't select "Undo" within the time limit, your message will be sent. "Undo send" may not work if you experience connection issues.