1991 Ford F150 Clutch Issue

The problem initially started with the clutch petal engaging closer and closer to the floor even though the resevoir is full of fluid. At that time, I could pump the clutch petal and it would engage more normally towards the top of the petal travel....it would then operate normally. Over time, it got worse to the point that I could no longer disengage the clutch alltogether and now it is stuck out of gear. Again, the fluid resevior is full.

Any ideas whats going on???

Thanks