catagories lost

Before 2 days, after i wrote a note my blog. i saw my all catagories are lost! i did not make any update or any thing. in my admin page or site page it wrote “there is no any catagories”.
i try to make a catagory with same old name, i receive ” you have allready that catagory”. but not shown in the catagory section.
now i see, some times catagories come back by self. some times gone!
why i dont understand. when they gone, my all notes shown as uncatagorized. when they come all notes comes their catagory.
can you help me pls.
my adress: http://www.kaptantahir.net/giris
msn: [email protected]