i understand how you feel, as i have some duplicate content as well. you see i used to write a lot of film reviews on yahoo and myspace since i was 13 yrs old, so when I got to hubpages, i just copied and pasted all my reviews from those sites. Don't get me wrong, they were all originally written by me, just on different sites. However, because they were on multiple sites, they were flagged as duplicate.
do you write on more than one site though? the reason i bring that up is because i know when I asked hubpages staff about it, they told me that if you put the same article on another site originally then post it on here, then a lot of times it will come up as duplicate. Even if you were the original author on that other site. Therefore, the only advice I can give you to avoid that is either make sure that hubs you publish here will only be exclusive to this site, like I did. Or you can just paraphrase every sentence you have in your hubs, so it won't show up as duplicate, as i know some hubbers do. I don't know if you want to go through that or not, but it's an option. anyway, i hope that helps.