
zza ni |

class wise there is the oracle curse (i think lame ,make u immune to fatigue).
as for sicken condition (as per the above ioun stone option:
-Aberrant Bloodline bloodrager is immune at level 8 while raging (which is funny, since your not fatigued you can enter rage - and this remove the sickened condition).
- sorcerer's Pestilence bloodline 3rd level ability (which can be taken vie eldritch heritage feats) make you immune to sickened as well.