Is your email hacked? Or on the other hand you can't sign in to your AT&T email account? Or then again you see a lot of emails in your sent organizer that you actually didn't send? Your email might have been hacked or abused. To stop this and to make sure about your account here is what you can do.
Change your secret phrase by visiting
at&t email login and tapping on "forgot secret word"
Change or update your security questions by signing in account's security settings
Download an antivirus software or buy it from a retail store
Audit contacts by watching that there are no obscure contacts and on the off chance that you discover any, delete them
Update your internet browsers
Given above are steps that you can do to make sure about your AT&T account that is hacked.