I have noticed that someone remotely had accessed my email account, and has sent SPAM to all my email contacts (almost 4000) of them who are all now cranky at me! I need to know what to do to stop this, and ensure my account is secure, without sitting on hold, and going through the phone system in an endless round and round. I need someone on line that can take hold of the PC and look at it-- to see what I can do--
Also check for Spyware / maleware, and or Viruses on your PC.
Malwarebytes is good, and also Avast.
One of those could have gained access to your Email software. If it shows the messages in your outbox it is most likely local. But I can also write a nice script that can do the same thing, and if you execute it look out, it will not even show up on your PC as being sent, but sure can get your address book, and send nice things to your friends.