Email hacked...virus..in a Mac?

Change your Gmail (and any other E-mail accounts) password to something extremely secure. Also, it may be wise to get yourself a password manager (such as 1Password) that allows you to manage all the passwords you likely have.

By the way, there are zero viruses for Mac OS. What likely happened is you have a relatively simple password that you use for many accounts and someone figured it out.

First, do not reveal any private info here - it is too dangerous in any open online forum.

Second, email addresses are bought and sold by the thousands daily; it is a "business". So, your email address(es) may have been obtained from somewhere else. There isn't much you can do except change your passwords. If the problem becomes too annoying, delete that email account and create a new one with a very difficult password.

Not sure what you mean by this:

no one gets bounce back messages.

Mail app has not offered a bounce back option for some time; it was never a good idea since that bounced email told the sender that he had sent it to a real "live" and usable address.

Sending you a reply which does not arrive has nothing to do with your Mail app - it is ruled by the sending or receiving server; in other words: their ISP/email provider or yours. Have you checked with your ISP or online email provider? And have you asked your friends to check with theirs? Those servers may have filters which detected a spam email and "confiscated" it = not delivering it. Using your email address as a "from" address will usually still show where the email actually originated, so that might be another explanation.

Hi Dana,

What all 3rd party extentions are you running?

EtreCheck is a simple little app to display the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support Communities to help people help you with your Mac.

http://www.etresoft.com/etrecheck

Also...

https://www.crystalidea.com/macs-fan-control