Can't shift smooth...

My 'teg is a 5-spd manual, and in the last two days of driving it has become difficult to shift into any gear. It doesn't matter if the car is moving or not. The car has 90K miles, and I don't know whether or not it has had a clutch replacement. My two guesses are:
1. The clutch is not disengaging fully. If the thing is out of adjustment, I would think the clutch pedal would feel sloppy, but it doesn't. Every other time I've noticed the clutch out of adjustment(on other cars) there is "play" at the top of the clutch pedal's range of travel, where pressing the pedal isn't moving the clutch.
2. The clutch needs to be replaced. This is the option that I hope is not true, for obvious reasons. However, it would make a good opportunity to upgrade.

Help!!