1990 Honda Accord clutch won't engage

I have a 1990 honda accord with a manual transmission. A while back I noticed my clutch pedal was progressively working its way to the floor. One day on the way to work at a stoplight I couldn't get it into first gear. I panicked and tried to force it into gear and it wouldn't go and made a clunking sound and seemed to go forward but not into gear. I have since replaced the slave cylinder and drained and replaced the transaxle fluid. My clutch still won't give me any pressure, and is stuck on the floor. No fluid has traveled to the slave cylinder. The master cylinder has its fluid and seems fine. What do you think is my next step in resolving this issue? Thank you for your advice