Sounds like you need to adjust the clutch.
If the clutch pedal is going close to the floor before there is any serious resistance, an adjustment is required. The gears are grinding because the clutch is still trying to transmit power even though you are stepping on the clutch pedal.
As the clutch disk wears, the pedal linkage requires adjustment.
If you don't know what you are doing best to find someone who does because if you adjust it incorrectly it can slip all the time and destroy itself.
Dave M7040