My clutch worked fine driving home from work. When I went to get back in it the next day, when I started it, the truck started to take off on its now. and now I have NO pressure in the clutch pedal when pressing it down. What can cause this? Clutch had plenty of pressure before and now none. Went into gears just fine without any grinding. I've got no idea. and I have no idea how to replace it myself.