Clutch slave cylinder

Stopping at a stoplight last night clutch pedal became soft. I was unable to downshift. Vehicle was stuck in neutral. Unable to get vehicle to go into gear, I had to be towed home. Today after pumping the clutch pedal I was able to get the vehicle into gear moved it forward and backwards a couple times. Then it would not go into gear again. Brake fluid was a little low so I filled with brake fluid. Pumped the clutch pedal a few times put into gear let clutch pedal out nothing happen. Vehicle did not move and did not stall while in gear pressing gas pedal engine just revs. Now with engine running I can shift through all the gears without pressing on clutch pedal. It seems like the clutch is disengaged all the time clutch pedal in or out.