Check the operation of your clutch quadrant . The clutch on these cars are sent from the factory with some preload , too much preload and the clutch wont engage properly , not enough preload and the clutch wont disengage properly causing hard shifting or not being able to put it in gear at all. If you have to push the clutch all the way to the floor in order to put it in gear or shift gears then you either have a worn cable that has stretched beyond its usefulness or there is a problem with something on the quadrant.
If the quadrant has worn teeth on it you may experience sudden loss of clutch where you wont be able to put it in gear easily or at all . Ive had similar issues where the quadrant slipped and was unable to change gears at all even with the pedal to the floor.