I think you may have a small tear in your medial meniscus, impossible to verify from here, but sounds like your symptoms. Id lay off squats for about 2 workouts and start back as pain through the ROM permits.
The larger question is easy. If you continue to eat to stay small, you'll be small. I really detest the emphasis by weight-class-sports coaches on making weight and staying small. They have no thought for the future health or athletic potential of the kid -- they just know that they need to fill a weight class. Short-sighted, selfish, and counterproductive.