if its hydraulic there could be air in your line. bleed your clutch and refill.
sounds like clutch needs adjustment or time to replace it
A worn out clutch release bearing would cause a whining sound when you put your foot on the clutch.
It's worn out, bad linkage or worn shift levers.
A problem in the fuel line could cause it to stall. On a stick shift, letting off the clutch too soon would cause the vehicle to stall.
Your car if its a stick is not pulling out of gear all the way and your moter overrevs
bad clutch cable, or not enough oil on the clutch plates.
Clutch is not adjusted properly.
There is no hydraulic fluid in the transmission. However, there is hydraulic fluid in the clutch system. If the clutch fluid reservoir is empty it would cause clutch not to operate.
Possible bad clutch will do it. Check to make sure that the trans fluid is full with the right viscosity and check the clutch, clutch master cylinder,& the slave clyinder in the transmission.
Slack in the clutch release or clutch basket. It might adjust out.
your clutch may not be fully engaging