97 Honda Prelude having some clutch problems...?

I have a 97 prelude, i was driving from sacramento to salt lake city when i was nearing salt lake, the resistance on the clutch started to go. in the morning there was no resistance and the clutch was either up or on the floor, no pressure. i checked the fluid level and it had gone down, so i added more fluid, we pumped the clutch and the resistance came back and the clutch was working perfectly. drove the next day to denver and the resistance on the clutch is going down again but the fluid level hasn't dropped. any suggestions on what the problem is and what needs to be done?