If I'm in stop and go traffic, my clutch pedal starts going away and today it would not disengage the clutch. I pulled over for a minute, let it rest and no more problems. There is no leak and its full of fluid. Its a 1990 S10 T5.

It sounds like you have a leak in your master cylinder through the seals. Basically its like bllow-by. When you press on the pedal, the master cylinder slides forward in the cylinder and displaces the fluid into the slave cylinder moving the slave out. The back force created by the clutch must be pushing the fluid back around the master cylinder seals.
I'm no expert but thats all I can think of.

If I'm in stop and go traffic, my clutch pedal starts going away and today it would not disengage the clutch. I pulled over for a minute, let it rest and no more problems. There is no leak and its full of fluid. Its a 1990 S10 T5.

You are boiling the fluid it gets hot and you will loose your pedal. It cooled and worked again. Get dot 4 high temp non synthetic.

Thanks for the info.