I am receiving mail from my own address daily which is sent to some other friends who is on my link?

I receive two mails at a times daily from my own address which i have never done by myself and same mail goes to 5 or 6 friends of mine, some of my employer, the place where i applied the job have received same mali from my address, as each time it sends to the different addresses which is linked to my address, this is not very nice to me and i dont know what is happening. Can somebody helps me what i have to do to get rid of it ?