Clutch issues?

[mccarf]

Sometimes lately when I've engaged a gear and I'm moving along, sometimes recently the car just "ignores" my throttle input in terms of speed but keeps revving if I keep pressing the accelerator. If I don't put the clutch or touch the accelerator in then the car just stalls once the revs drop. Even in first gear which normally just drives along with no throttle input the car just stalls. Is this the clutch "slipping"? Never had these issues before so I'm a little confused. It's done it quite a few times now, and has left me in the middle of a busy roundabout which was quite unpleasant so I'd like to get this resolved.