I wouldn't.
That is usually a spammer spoofing your email address so it looks like you sent it. In your email program, there is an option to View the Message Headers. That reveals all the places that your email was routed through, including the original sender's IP address.
If the headers reveal that it came from your email address, and not a CC or BCC, you could have a virus. Some viruses will use your computer to send emails from "you" to people on your contact list. Make sure that your anti-virus software is up to date and do a scan to ensure your computer is not infected.