Those calorie calculators can be kind of misleading because there is no real way to factor in your specific metabolism. We're all so different and have different nutritional requirements that any sort of blanket formula should probably be used just as a reference point. I'm pretty sure 2880 calories would be for someone who is very heavily muscled or runs marathons or something 'cause that does sound like a lot for someone who is 5'5"
I would suggest, since you've already been tracking your calories, take a look at what you've been getting, compare that to what your weight's been doing and adjust from there. Do be careful not to go too low though - not getting enough calories can slow down your progress just as much as getting too many.