Was it originally posted to Tenchiforum, or TMFFA? If it's the former, we might not have a backup from that long ago if it was indeed pruned. If it was from TMFFA, you can try browsing via the wayback machine to see if your fanfiction was saved there.
We will eventually have a live backup of TMFFA active, but if you're pressed for time, I recommend checking out the link above. Apologies for the inconvenience!
If it isn't available there, could you let us know the name of the fanfiction and what name you might have posted it under?