Losing an entire planet won't do it?

It might for most, but Vulcans are (inconsistently) good at swallowing this stuff. Something had to hit close to home for him to beat the space chlamydia out of Kirk, in public no less.

Of course, if we follow precedent from The Immunity Sydrome then we might ask why Spock wasn't incapacitated with psychic whosits when all the Vulcans died.