Sounds very strange. The only way I can see for this happening in if maybe one of your friends that has your email is accidentally sharing it in some document.

If people are somehow getting your email through your Limewire this is the first I have heard of this happening.

Where did you download Limewire from ? (Slight possibility that you got a bad copy somewhere with spyware embedded into it)

Official site is www.limewire.com (Adware and Spyware free)