3x8-10 is dosen't have to be fixed 8 all the time, pick a weight you are just comfortable with and use that. Post workout nutrition is extremely important, so is eating on days you don't train. When doing cardio you must have carbs before and after workouts otherwise you will lose muscle. You need protein every four hours to build bulk and to prevent catabolism (muscle burning), do it properly otherwise you will only be wasting your time and prolong the amount of time it takes to get anywhere.