Only rely on protein so much. If your drinking a shit ton of it your body is passing alot of it as waste. Try to eat more real food eggs red meats chinese ftw. lol All serious tho dont worry about weight so much as how you feel and how you look. weight is just a number. I was my strongest when i was as light as ive been in 9 years. If you want to put on size stick to your core lifts. Your squats deads cleans bench. Im 26 been lifting since i was 12. Definatley don't know everything there is to know. The best thing is to you got to find what works best for you and what you like as it wont be the same as everyone else. Stick with it and go hard.