You should first check to see why the reservoir was low. I don't know if it goes down over time as the clutch wears but it could also be a leak somewhere like at the master cylinder (on the firewall side of the clutch pedal) or at the slave cylinder (at the transmission).
My older S10 showed the same symptoms. It turned out that the rubber hose line between the reservoir and the master cylinder was deteriorated and fluid was being lost. I replaced the rubber hose, bled the system at the slave cylinder, and all's well. There's no cost to check this out and it could be a cheap fix that may get you going again.
The following is from
www.autozone.com Vehicle Info - Vehicle Repair Guides
HYDRAULIC SYSTEM BLEEDING
Have an assistant fully depress and hold the clutch pedal, then open the bleeder screw of the slave cylinder or concentric cylinder using a box-end wrench
Bleeding air from the hydraulic clutch system is necessary whenever any part of the system has been disconnected or the fluid level (in the reservoir) has been allowed to fall so low, that air has been drawn into the master cylinder.
1. Fill master cylinder reservoir with new brake fluid conforming to DOT 3 specifications. Check manufactures recommendations for each vehicle.
CAUTION
Never, under any circumstances, use fluid which has been bled from a system to fill the reservoir as it may be aerated, have too much moisture content and possibly be contaminated.
2. Raise and safely support the vehicle high enough to work comfortable under it.
3. Have an assistant fully depress and hold the clutch pedal, then open the bleeder screw of the slave cylinder or concentric cylinder.
4. Close the bleeder screw and have your assistant release the clutch pedal.
5. Repeat the procedure until all of the air is evacuated from the system. Check and refill master cylinder reservoir as required to prevent air from being drawn through the master cylinder.
Never release a depressed clutch pedal with the bleeder screw open or air will be drawn into the system.
6. Lower the vehicle and test clutch operation.
7. If the previous steps do not result in satisfactory pedal feel, remove the reservoir cap and pump the clutch pedal very fast for 30 seconds. Stop to let the air escape, then repeat the procedure as necessary to purge all remaining air.
8. Check the master cylinder fluid level and replenish as necessary.