TRB mate, as well as the food that you are gonna be eating if you want to build muscle mass rather than just tone up you have to do a different type of exercise.

Lifting a tiny little weight say 100 times aint gonna do nothing in terms of strengh but will help stamina. Its strengh that you need to build in order to get bigger.

Go down the gym and see what weights you can hardly lift. Then pick the next one or two down the scale and lift these maybe 3 to 5 reps. When you cant lift anymore immediately grab the next weight down or two, and lift this 3 to 5 or whatever you can now physically lift, and so forth until you get down to just the bar and cant lift it!! lol.

This is called pyramid, trouble is if someone comes in and sees you on the final weight lol and really strugglin

HTH.