Sometimes the links between the friction and pressure plates break leaving the clutch noisy as hell with pedal depressed and the whole lot out of balance with pedal released. Smooths out after 30 seconds of centrifugal forces centering things up but basicly sounds like 'tis time to replace clutch plates, throw out bearing, slave cylinder and gearbox input seal. Also check if flywheel still ok and gearbox bearings.
Has it got a gearbox drain plug? If so see if there are any shiny bits in the oil sometimes the plug is magnetic, if its all furry expect a lot of wear inside.
First thing to do is separate the box from the motor and see what falls on the floor and work from there.
Good luck.
