I'm not expert in these things but it also happened to me before freestyle, well I normally freestyle like 5-6 hours maximum when there's no exams/stuyding etcs, about the 2500 calories, I eat much more than that, (pretty hard to say what I eat because of the arabic food which almost doesn't have a name in english) I always try to eat until I get full, but I dont see any changes, but nevermind anyways, I think I have to gain muscles in order to get fat.
Your stomach is small then and you can't eat more than that unless you're using the energy in which I said what to do if you eat too much. What foods do you eat, I might know them. If not, tell me what's in it? How many times a day do you eat til you're full? Try eating 30 minutes after you've eaten the most you can eat to keep your stomach expanded. It will take you a few weeks before you get used to eating more than you burn. Also water. Drink lots of it.
Would you say this is a lot?
2-3 Eggs, 2 Sandwiches of tuna, Quarter chicken, 3 Carrots, 3 Cucumbers, 1 Banana, 1 Apple, small bowl of Pasta, Cottage cheese, Regular sized hamburger.
Everything self made.
SPOILER:
It's around 2000 Calories, the amount the average(no exercise, 9-5 job) person is meant to consume.