Please help, car shaking uncontrollably

Ok, i dont like to admit it, but i occasionally grind my gears. I did it today again But the problem is that when i stop the car after i have done this, and start off in first by adding gas and slowly letting go of the clutch, the car shakes like crazy. Adding more gas doesnt help, its not like its about to stall. But if i let the car rest for lets say 12 hours, i can drive it normally again without any shakes. This has happened everytime i grind it. Does anyone know what this could be. My car is a 2001 V6 manual. The dealer wont be open till monday and i just want to hear what you guys think.

ok i guess i didnt give you guys the full story. I bought the car in April of 2003. I had a 6 month warranty from the dealer so every little problem i had, i went over there for them to fix it. Well my clutch pedal was rattling and i needed an oil change so i had them check out the rattle. They put some tubing on the cable and it went away for a couple of days. Well then i had another small problem and at the same i had them check the rattle again. Well...they went nuts and replaces the clutch, the pressure plate, the throwout bearing, and resurfaced the fly wheel. Got it all for free so i was happy.
Well its now January of the next year, and i've only ground my gears like three times, but its becoming more frequent. So i went to a local ford dealer, went for a road test with the guy and he came up with "the clutch is rattling, could be the pressure plate, they would have to drop the tranny." He said it was weird how it goes away after a while. Said to go to the dealer where i had all the other things done because those parts should still be under warranty. He also said i was grinding so often because the pressure plate could not be coming back...
Gonna have to see what the dealer who sold me the car said.