At you current weight, it is probably OK to eat that much. Are you on a medically supervised program? If so, then you should continue to follow it exactly.
If you're doing this on your own, how are you tracking your calories? Do you use a computer tracker, or a book and notepad, or...?
If you tried to eat 2100 cals of lettuce, you'd never get there!
So as Soulbliss suggested, try more calorie-dense foods. Plus to make sure you have enough protein, you may be able to double the amount of chicken, beef, tuna (if you eat meat/fish) for a meal. Or, more nuts, more tofu, 3-egg omelets, and so on.
Don't head for the ice cream, though! That's the wrong idea...