And I am getting emails telling me that friends and family have added me as a friend on their Facebook accounts even though I don't have a Facebook account.
It is always a good idea to change your account passwords regularly. That will be of some help though it may not solve your problem.
I was recently getting "undeliverable" messages regarding emails sent from my account, but not by me. I responded by deleting everyone in my contact list, which cured the problem, but of course I have the problem of remembering folks' email addresses.