So the past week my average calorie intake was 100 or so. Am feeling really sluggish and dizzy today, but I'm scared I would get fat if I don't go for my daily routine exercise which I try to stick to. Should I do it? (300 jumping jacks, 30 situps, 4km run). Feeling super dead right now, scared I would faint but I am pretty fat (BMI 17) so I have enough fat store to burn why am I tired???