95 Maxima clutch problem???

ok my girlfriends car has been acting weird all of the sudden. when you are just driving, not accelerating, just moving like in 3rd gear for example (its a standard) it revs out of no where but doesnt accelerate just revs as if it would if you had the clutch in. does this sound like a clutch problem??? like maybe the clutch is slipping??

thanks everyone!

any one know?