Clutch concerns

So I put a ford motorsport HD clutch in my car over the summer. I was happy with the way it felt when I put it in. Earlier tonight, I was driving a buddies car, a 2002 GT, and the clutch very springy compared to mine. When I got back in my car, my clutch felt horrible. It was very spongy feeling. Being that this is the only car I drive, I'm not sure weather the clutch was like this before or got this way gradually. Either way, it doesn't feel right. It definetly feels different after driving the '02. I think I'm going to get up under it tomorrow and check the cable to see if it has come out of adjustment. Anyone else ever have this happen or have any similar experiences? If it's not the cable just needing to be tightened up, what else could be causing this spongy feeling?

I am running an adjustable cable. The adjustment point is where the cable goes into the tranny. I'm changing my oil tomorrow anyway so I might as well check it out while I'm under the car. Hopefully it just needs adjusting. It just seems wierd how much of a difference it seemed like. I can't believe how spongy my clutch feels after driving the stocker. It's horrible.

Anyway thanks, keep the advice comin guys....