I drive a 2014 1LT manual Cruze, I got the clutch fluid changes at 45k miles. Soon after I was making a 4 hour drive and halfway through I needed to change gears but the clutch pedal went to the floor, and the clutch was still engaged. Once the car cooled down again the clutch began to work fine, but if I take a longer drive I start to notice the clutch pedal becomes stiffer while still being able to disengage the clutch. I am thinking the brake fluid is getting too hot and the hydraulic system is failing do to that because heat kills hydraulic systems. But I am worried it might be something more severe.