That's a bummer man!

Fortunately, It takes less time to re-write that code, because you probably remember what stuff you added/changed. Just do that ASAP, so you don't forget. Also, harddrives are alot safer for storage. I have 2 USB-sticks but I don't use them that often (I use google docs, SVN and SSH (on linux) alot, so I dont have to carry my stuff with me).