Clutch Doesn't engage anymore?!

Hi everyone i recently bought a 2007 Pontiac G5 SE manual transmission and it has 185,000 km in it. It was pretty smooth and normal for the first few days but then i started noticing something weird. Im very new to manual transmission cars but i know exactly how to drive one. The problem i noticed was when i get to about 100km/h the more i press down on the gas pedal nothing would change in the speed and the revs would just go higher until they approach the limiter. I ignored it and continued on using the car for another 3 to 4 days and suddenly one night as im driving home something weird happened and it felt like the transmision was gradually not engaging causing the revs to go higher and higher for me to reach sppeds like 40 km/h until i reached my parking spot and the car wont move at all despite the engine revs going all the way to the limiter. Im so puzzled and confused and i feel like i got ripped off cuz i literally owned this car for like a week now. does this mean that the clutch went bad? i didnt hear any noises in the clutch... I also noticed that i can shift the shifter to any gear without stepping on the clutch? what could that mean? I need all the help you can provide me with, thanks!