my clutch stopped working today.i was driving and tried shifting down and clutch went all the way to floor and stayed there. if i lifted it up and then tried putting it in to put in gear wouldnt let me and clutch stayed down again.after a 1/2 hour i tried it again and it worked then about 2 miles it did it again.then after sitting worked again. what up?what do i need to do to fix problem?