I was driving normally (no problems, everything going smoothly; never had felt any problems with the clutch, was catching on well etc.) and all of a sudden, with no warning sign or anything (no shock, no bang, nothing), the clutch pedal doesn't go far enough anymore to engage the gears in a normal way. I was still driving and it still worked more or less (but it was bumpy changing gears, as one would expect, and not very healthy for the car, I think), so I stopped at a place where it was safe to do so. It goes about 3/4 of the way, then there's a lot of resistance and I can't push it any further -- it's not just hard to push further, it's impossible (unless I would put so much force on it that it would break or something).
I didn't want to drive it like this (can't engage the gears unless I would put too much force on it, which I don't want to do), so I left the car at the safe spot and asked someone to come pick us up and we'll have it towed tomorrow.
Does anyone know what it might possibly be?
The car is a BMW 320D E46 built in 2001.
EDIT: the clutch pedal works again -- I don't know how this is possible, but it's still not going smoothly, so it was certainly more than just an obstruction of the clutch pedal. When I shift and slowly release the clutch while pressing in the gas, it's supposed to be smooth, now it's bumpy. It's technically speaking drivable, but it's everything but a smooth ride.