It's likely a clutch master cylinder and/or CSC bearing issue. If so, it is a good time to replace/inspect the flywheel, pressure plate, and clutch since the manual transmission will need to be removed to access the CSC bearing.
Another tip is to replace the stock clutch pedal with a aftermarket clutch pedal. See this forum for clutch pedal replacement.
I had my 370Z transmission replaced along with the CSC bearing covered under warranty.