In acute conditions think of Veratrum when the sufferer is exhausted and faint. They will be extremely cold but peculiarly they have an extreme thirst for ice and cold drinks (which they may vomit up soon after).
They may be exhausted and totally drained from their diarrhoea or vomiting but the important signs to look for are the coldness and the restless agitation even though they feel washed out.
Restlessness. agitation.
Cold sweat
Very thirsty for cold drinks
Worse eating fruit (compare Colocynth)
Diarrhoea
Fever
Tiredness
Vomiting