Coupling defect?

Data about the car: Honda Civic 1.4 90hp EJ9 Hatchback Hello, I had a problem and I did not have a problem a few days ago, I accelerated my Civic from the standstill and when I wanted to get out of the 1st into the 2nd gear, the clutch pedal felt funny at this moment and I couldn’t put in the second gear any more. The clutch pedal comes back to its position quite normally, but when I press it seems a little lighter and shortly before the close one you run a slight counter pressure. When the car is on, I can’t put in the gear. Once I have switched off the car, I can switch the gears normally. I then turned off the car, put in the 1st gear, put on the car and wanted to go off. Only from about 3500 revolutions the car moved slowly forward and the gears could not be changed. Then I did a clutch test (with the 4th gear and tightened hand brake) and I was able to give in the standstill and plugged in gas and it is not dead. Liquid is present, it is not checked today. What is the coupling cylinder should start here?