USB flashdrive-memory stick

I have a Lexar USB memory stick. I am working on it almost every day to save my Word Doc. files. I left it on in the USB slot all times never pull it out after using it (Should I or should not keep it in?). I had it over a year.
I save my files under MS.Word for Window 2003 (too old) but it was working fine until yesterday.
Now I ran into trouble, my computer didn't recognize it after I boost my computer. I took it out. Put it back in again. My USB memory stick flashing continuously, for 2 hours or more non-stop. But I refresh my drive. I still get nothing. I am sure nothing wrong with the USB slot, because I put another USB stick, It's OK.
Please give me an advice what can I do to retrieve my files

Thank a million for your help.

Morrow, Mua