it is possible it is a disease cuz in those temps she should be smart enough to go inside unless something was wrong before but i still think it is hypothermia from being out in cold all night.
i think she is still to cold internally and not retaining body heat and in shock and not eating enough. if i remember right fast warming, dry heat. ours took about 5-7 days to actually be up again moveing totally and walking. antibiotics will help clear up or prevent scondary infections but at this point i see no reason she needs it but it won't hurt either.
u need to get her to eat anything u can at this point, hard boiled eggs chopped up, scrambled eggs, yougert mixed in feed, fruits, warm oat meal anything u can get her to take to get the vitamins and keep hydrated. she definately need vitamins in her if she is not eating enough and sugar water will help to make warm inside and give energy. cyeane pepper sprinkled on food helps warm and circulate blood to if u can get her to eat something with that on it.