cognitive scientist man
The real problem is not in establishing whether you yourself are a p-zombie, but whether everyone else is.
Are you afraid that if you answer me, it'll set a precedent that you do all your cognitive sciencin' for free? Because I can't pay you...
Well, the p-zombie argument generally assumes that you can nail down the fact that you are conscious because you have first-hand experience. (Cogito ergo sum and all that, though you can even doubt that if you want to be a radical skeptic about it.) A zombie would not be self-aware, but would only act like it. The problem then is extrapolating that to other people and/or zombies.