I would be mortified too. The only people who have read anything of mine are my sister and my mom, and that was a way long time ago. When I first started writing fanfic, I was 14, still living at home and sharing a room with my sister, so it was hard to keep it a secret from her; she knew pretty much all along, and she read some of my early stuff, but then she stopped liking BSB and just made fun of me for it. I think my mom read a little of my very first fanfic when she found out about my site, but I was embarrassed and told her to please not read anymore, and she said she wouldn't. To this day, I honestly don't think she does... I think she would have mentioned it by now if she did. Also, I have a good site counter that tracks IPs and locations, so I can see if anyone from where I live visits my site LOL.
My friends don't know anything about fanfic, and I plan to keep it that way. Honestly, even though I have this goal of someday writing a novel that could be published, I'm not sure how I'd ever have the guts to actually publish it. I'd probably do it on the DL and not tell anyone except you guys LOL... which kind of defeats the purpose.