WordNet sense 1 (causing or able to cause nausea):

loathsome, nauseating, nauseous, noisome, offensive, sickening, vile

WordNet sense 2 (detrimental to physical or moral well-being):

unwholesome

WordNet sense 3 (feeling nausea; feeling about to vomit):

nauseated, sickish

WordNet sense 4 (affected by an impairment of normal physical or mental function):

ill, sick

WordNet sense 5 (causing or fraught with or showing anxiety):

anxious, nervous, uneasy, unquiet

WordNet sense 6 (characterized by or indicative of distress or affliction or danger or need):

troubled