Shilo, your only 19 so don't worry the size will come. Remember that your body is still growing at that age. As for bulking up before you head into the Army, I wouldn't worry about that so much because boot camp will put some bulk on you. Keep focused on your running though because you'll need that stamina come boot camp. Trust me I was in the service. The more stamina you go in with the better off you'll be. As for protein shakes I recommend Optimum Nutrition's 100% Whey Protein. It is fairly cheap only $20 so it won't break your bank, very low in fat, tastes pretty good and mixes better than anything I've used before. Drink that with some milk to up the calories and it should do you just fine. Plus if you use two scoops you'll get over 40 grams of protein per shake and that's about as much as your body can handle at once, any more than that and your body will convert it to fat. Drink 3 shakes a day and get the rest of your protein from food. Remember the rule of thumb is 1 gram of protein per lb of body weight so you should be intaking 150 grams of protein a day. Good luck in the Army and when you get past boot you'll be in the best shape of your life.