New answers tagged security
If that was a spammy link, and you clicked it, that must be the cause. It happens many times that an unknown link is sent by your friend, and the moment you click it and perform some actions, your account gets hacked (sort of), and then many automatic messages goes out from your account without your knowledge. And it won't show in your account activity ...
There is no such thing as a "guest" account for your Google account. If you give someone your password they'll be able to see everything in your Google account, including the contents of your Gmail.
I would suggest contacting Google Support more than likely someone either entered the wrong address for their account recovery information or they're Phishing. You can contact google through their contact page. Either way Google's support teams are usually very helpful at getting these issues sorted.
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