1998 Ford Escort clutch

I have got a 1998 ford escort GTI, I have had the car a year now. Last week I was driving up to a junction and pressed the clutch down but the car seamed to be grabing and the engine judered when I breaked. The clutch still works beacuse I can engage and disengage and change gear fine. It just keeps holding on if you are moving and press the clutch. It almost seams like when you break without presing the cluch you get that juder. Once it does that for a minuit it then relases and works fine. Since this problem has arisen when you idle with the clutch down the revs bounce up and down all over the place, it sounds like you keep blipping the throtal but I am not. Any suggestionbs on what this can be