Basic mechanics.
The clutch is released by a pressure plate that has spring fingers that are pushed on by the thrust bearing that is pushed on by the slave cylinder. The slave cylinder is hydraualicly driven by a hydraulic master cylinder attached to the firewally and connected to the Clutch pedal by a shaft that passes through the wall.
The fingers of the pressure plate create force that pushes the thrust bearing back which pushes the slave cylinder back, the hydraulic fluid back into the line and pushes the clutch pedal back up via the master cylinder.
if the pedal doesn't come back very far, that is a sign of either pressure being bled off, or wear of the clutch disks is significant enough that the travel of the slave cylinder no longer allows it to push back enough fluid to lift the clutch pedal as far as before.
If the pedal is sloppy, this could also be a sign that the spot in the pedal where the shaft from the master cylinder attaches to it has become worn and should be repaired.
Try parking on flat ground, put the transmission in first and hold the clutch pedal down. The car should not move. If the car starts to move, your clutch disk is probably worn to the point that it will be failing soon. It's easy to tell as you'll go into second gear, put the hammer down and during WOT, you'll feel the engine lurch as the clutch slips.