Have a look at this link: www.cnet.com/forums/discussions/how-can-i-stop-spam-that-is-using-my-own-email-to-email-me-609198/
I think it about covers the issue. I think I would consider changing to a different email provider as suggested. I get hardly any spam at all (I probably shouldn't have said that - but it's true at the moment). The only other suggestion I have is that if you send out an email to a list of recipients, use the blind blind copy (bcc) function so that no recipient sees anyone else's email address. Also encourage friends and family to do the same. Sending out lists of email addresses makes everyone more vulnerable to the spammers. Good luck.
Another welcoming into Soop's kitchen for those who care to share...