i would put your car up on jacks or on a lift... open up the tranny covers where you can see the pressure plate once opened... and see if the pressure plate bolts that bolt up to the flywheel is loose or not..
also check the fork and clutch cylinder that pushes on it (pushing the throw out bearing)
if all those seem to be working properly i think your clutch is starting to wear out.. unfortunately.. sorry to hear!

i know the feeling though!!! ask me how i know
argh!