Why am I not gaining muscle?

I've been uping my calories to 2000 calories a day and I've used my protein to 144 grams of protein a day, but I haven't gained any weight. In fact I have lost a pound. I am really frustrated because I want to gain muscle so I can join the USMC at the end of my senior year of high school and I am a junior now. So what am I doing wrong?
Why am I not gaining muscle?
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