Well the good news is that your character is still there. The website, to use a Cryptic technical term, is "Janky". However, you can create a character on the Public Test server. Not as good as porting your existing upper level character, but....
I was not in the game half a year
I want character in the public test
I think the Tribble Toons get Wiped Now and Then to prevent Carryover Contamination to new Code being Added. As BDS says, you can Create a New Toon there, or you can Copy an Existing Toon from Holodeck. If you check the Tribble Server Section of the Forum, there are instructions there as to how to copy to Tribble.