My nails are quite blue, skin is cold, can't get it warm and temperature 35.5c. have dysautonomia. what can cause this?

Low body tempertatur: Core temperature <95 f (35 c) is hypothermia. Adrenal insufficiency, sepsis, hypothyroidism, severe psoriasis, wernicke's encephalopathy, benzodiazepines or barbiturates or phenothiazine toxity can cause this as well as alcohol intoxication. A visit to an endocrinologist would a first stop since you are conscious and thus with an illness that is compensated with a homeostatic mechanism.