i doubt youre anywhere close to "built" at 135 pounds and 5'9. More of a skinny dude with low fat. You need to bulk up so find your caloric maintanance and eat above it. No one can tell you how many calories you should eat, it is different for everyone. Weigh yourself and eat (for example) 3000 calories a day for two weeks. Weigh yourself again and see if you inceased in weight, decreased or stayed the same. Adjust your calories if needed. Remember you only wanna gain 1 pound a week MAX to minimize fat gains, but you initially might gain a few extra pounds when you start.
Dont be afraid to lose your 6 pack if you have one, trust me get a 6 pack when you put on some muscle.
Another thing, check your weight when you wake up after taking a crap/piss.