No, it's not so much the simulation hypothesis. The simulation hypothesis would be a bit more bearable, because at least then reality is as real as said simulation and everything therein is as "real" as the context makes it. My actions and life within might be simulated, but the simulation is still a definite reality.
However, if my examples were true and I were comatose and dreaming or massively hallucinating, then what I know is not "real" by the standards of the surrounding world, because I'm not seeing it as it is but how my mind creates it.
Basically, the fear is less "The Matrix" and more "A Beautiful Mind."