easy fix .
protein is the most thermogenic of macros. 100 cals of protein requires 30 cals of energy to assimilate. your basically burning 500 cals per day just to digest that amount of protein. thats like 2 hours of cardio per day. no wonder you can't gain and your metabolism is revving so fast.

drop your protein down, up your carbs and up your fats big time. this will slow your metabolism down, conserve energy, and allow more food to "stick" to you.. I would add fats to every meal to help slow down digestion as well.

280g protein , 450g carbs, 150g fats. .. thats 4,270 cals .

your going to grow much better off that then what your doing now with super high protein and low fat


and as Nephets stated, make sure those macros are all nutrient and micro nutrient dense