1987 Mazda RX7 Clutch Problem

I have noticed in the past couple of days that the clutch pedal seems to be getting lower to the floorboard before it engages. Tonight the car had sat for 24 hours when I started it and noticed that there seemed to be little cluch pedal and that the shifter would not ge into gear immediately. I pumped the clutch pedal several times which allowed me to shift gears, but still with very little left with the clutch pedal. I was afraid to drive it for fear of getting stranded away from home. A few years ago I had the clutch replaced, then later had the master cylinder for the clutch replaced and then a while aftrer that had a vaccum line (according to the mechanic) replaced that was leaking and preventing the transmission from shifting. I checked the fluid in the master cylinder and around that area for leaks with no problems. There is no evidence of a burning smell or unusual vibration when driving.
Do you have any suggestions on what the problems might be.
I have a reliable local mechanic here in Hurst, Tx., however he does charge to diagnostic work.
Thak you in advance for any assistance that you may offer.
Take care.