weird

So I've been using the myfitnesspal.com to count my calories and today it insists that I'm not eating enough, even though for breakfast I had orange juice, cereal and milk, lunch was chicken leg asparagus and potato, dinner was sang choy bow, so basically chinese pork mince and vegetables in lettuce and then i ate the rest for snack (400g!) and 4 chocolate drops..very odd indeed. Still says I need like 420 more calories and that I'll put my body in starvation mode. I don't know if it's because of all the water i'm drinking but I'm full!!! Who would of thought that dieting would make me eat at 10.30pm because before I did it was over 600kCal I was missing!?