Hi,
yeah could be "NAC FLU" or Porhyria caused by the NAC you took affecting any existing C.pnuemonaie infection.
look on cpnhelp.org and search nac flu and porhyria. Personally I get the above symtoms you describe when I kill off too man cpn at once, which for me is porphryia symptoms. Also I am unable to take NAC because I get too much of those nac flu symptoms as well.
However, y ou may not have a cpn infection, it could be toxiity/detox overload. instead.
As for testing for cpn, I found the Arminlabs tests pretty good. but do your own research more, cpn is still an experimental field and there is no guarantee it will work to cure you even if you have it, that is the problem, so deciding whether it is worth undertaking a treatment which will be long and hard is a diifficult one. Perhaps the best research in MS or heart/cardivascular disease on cpn. Good luck.