you're not completely fucked.. im too lazy to explain and shit but google "hardrive recovery software"
ive recovered a few hard drives before. The faster you act the better.. you dont actually delete the stuff on your computer when you reformat you just delete the path to it so thats why it doesnt show up on your computer anymore.. it's all there tho, or most of it.
For future reference.. dont format, just do a fresh install of windows. It'll keep your files but do a fresh install of the corrupt files in your registry and computer.