No it isn't they aren't coming from you but someone using your email address in the from field, which is easy to forge. The possibility is that a friend, colleague or someone that you have corresponded with is infected and your email is in their address book. The malware on that system harvests email addresses from that system and sends emails out to try an infect other systems.
This is a common tactic as emails from you would if you had get through any anti-spam filters as your email address is likely to be white listed, so is trying to get by weak defences.
Fortunately your email server scans emails, but it is likely that avast would also have detected it, so at least you have two lines of defence.