It's more likely that a spammer is spoofing your email address, probably having gotten it from somebody else's address book. If that's the case, there's nothing that you can do except wait for the annoying messages to slow down.
What he/she said.
This is an attempt by some rectal-leaking, knuckle-dragging miscreant to get people to click on the link "http: //bit.ly/" and the come-on is weight loss. The site could as easily be pharmaceutical (usually viagra or cialis) or porn or whatever.
This "person" (and I use the term loosely) is sending a(several) dump mailing(s) to a black-market list and what you are seeing is the returns bounced by bad addresses. They come to you because you are the (fictional, spoofed) sender.
You have my sympathy. These black-market address lists can have a million (and more) entries.......