Look to make sure your Hydraulic fluid level is full for the clutch. It is located near the brake master cylinder(see owners manual) . If it is low, fill it and pump the clutch pedal a few times and see if that takes care of it. If it doesn't then I would be looking at replacing the slave cylinder and master slave cylinder for the clutch. If it is completely empty and you fill it and pump it a few times, and its back to empty. Yes, you guessed it, look for a leak.