peaky

lousy, sickish

nauseated, nauseous, qualmish, queasy (also queazy), squeamish

airsick, carsick, seasick

dizzy, light-headed, shaky, woozy

achy, feverish

diseased, disordered

decrepit, feeble, fragile, frail, infirm, invalid, sickly, weak, weakly

afflicted, troubled

challenged, debilitated, disabled, halt, incapacitated, lame

hypochondriac, hypochondriacal