(This might belong in the training forum...?)

When you say "a lot of food", what does that mean, exactly? Can you give us an average day? If you're anything like me, you might be overestimating what you're eating. I was overestimating my diet by a solid 1000 calories, maybe even a little more. Also, are bench, squat, and power clean the only exercises you do, or are there others in this routine at school?

Your numbers seem pretty good though, so just keep eating and remember that your body wants to get 1.5-2.0 g of protein per day in order to grow.

Also, man, if that's your picture from fairly recently - you look fine, your arms don't seem that small in that pic.

Good luck bro.