[17Hatch6MT]

I'm curious, I have a manual too. I detected it getting a little rough feeling once when I was in some heavy stop & go traffic (outmaneuvering a city traffic jam by taking side streets). But nothing like this.

The connection from the pedal to the clutch is through a hydraulic line. Is there a fluid reservoir you can check? Usually would find it in the on the firewall in the engine bay, by the clutch master cylinder (behind the clutch pedal).

If the fluid is low, you might get by temporarily by replenishing it. If low, you have a leak somewhere and it must be serviced.

How cold has it been? Maybe there's water in the clutch housing and it's condensing and/or freezing on critical pieces? If this could be it, a long drive to get everything thoroughly hot might fix it. That's a long shot... just a thought.

Did you use it in an extreme fashion getting your car unstuck?

 

[17Hatch6MT]

Had this problem in April. Dealer initially refused to cover anything under the powertrain warranty. After working with GM customer care, ended up that the slave cylinder/release bearing was warrantied but the hydraulic parts external to the trans (incl master cylinder) I paid almost $1000. The car had 20,500 miles.

Now have occasional brake pedal sinking too. If I have to get this repaired, it'll be an independent mechanic. No more dealer. This will be the last GM car I own.

Entered cases on the NHTSA website for the clutch failure and then also the brake failure.

After 25 years owning two Japanese-make cars that gave very little trouble, I think I'll pay close attention again to a brand's repair reputation. My rationale for buying this was that it was Gen 2 and they'd solved the problems of Gen 1. That and a relative had bucks on a GM card (false economy, it's clear now). Didn't occur to me that (a) they didn't solve them all and (b) there would be a raft of new ones. I live and work in a city and can get by with my bicycle, and that was also on my mind as I bought a GM. I got along OK w/o a rental or loaner for the two weeks it was out.

 

[17Hatch6MT]

I'm not a mechanic, just have average smarts and above-average willingness to shoot off my mouth. That said:
Should be self-adjusting. May be air in the line, so, Try bleeding the clutch. I don't think this would be hard except maybe for access to get your hand in there. If there's air in the line, something is wrong & the fix may not last.