The amount of calories changes to keep you on track to your goal. If you think the number of calories is too low you should adjust your goal to one that is more achievable. Either a longer timescale, higher weight or you could do more exercise to get to your goal faster and leave the calories as they are. If you lose weight faster than the programme calculates it will allow you more calories, if you are falling behind it will reduce your calorie allowance.
R u working out or exercising because that will require you to eat more since your body used up the food you ate.