1. I'm damned if I've ever heard of extreme calf muscle fatigue from squatting. the calves are involved, of course, but primarily as stabilizers of the knee angle and are functioning isometrically over a very short ROM. I'd need to see this squat you're doing.
2. I think you're on the right track. Gain weight with lots of good food, and keep the gooey carb intake down to a minimum. Milk is good food.