Does anyone else feel sick if they eat like how they used to?

So it's only been 4 months for me of being in a deficit, but I've noticed that if I have the occasional day where I eat 2000 calories or slightly more than that, I start to feel quite sick. I'm 5'3, female and sedentary so my usual daily calories are about 1,500. I will eat a bit more if I see that my calories for the week are a bit low, but I find it hard to do a lot of the time. I can usually get to 1,800 but by then I feel so stuffed full of food. It's interesting because my appetite is still high but I tend to regret overeating now from how physically uncomfortable I get. Anyone else?