Updated iTunes, iPod classic erased? iTunes now doesn't work either.

Okay so I have a mac book pro, and I updated my iTunes recently as well as my computer system. I charge my iPod Classic in my computer, and the next day when I turn it on everything has been erased!! This happened once before but I just went into iTunes, returned to factory settings and re-synced my iPod. That is the only time my iPod has not worked for me. So naturally I went home and tried to do the same thing, but when I went into iTunes it froze, and stopped working. I tried force quitting but it wouldn't even let me force quit! So i tried to restart my computer and that didn't work either.. so I turned off my computer by holding in the power button. I've tried this 5 or 6 times and it's doing the same thing over and over. iTunes freezes, won't force quit.. I just want my music back please help.