How do you know when your overtraining?

[nksz90]

Friday was my leg day and for the past two days i could barely walk. My legs are freaken killing me.

Did i work them to hard? this is what i did:

squats 3x12
calf machine 4x12
leg press 4x12
leg press (calves) 4x12
standing leg press 3x12
different calf machine 4x12

By the 12th rep, it was semi failure.

[Blindfaith]

you arent overtraining....you just did one to many of the same kinda exercises, you need to throw some hamstring exercises in there.