Thank goodness you have not tried gear yet. With a 135 x 10 bench, you have a lot more natural potential in you to be used. Are you going to damage in the bodybuilding scene or are you a pro athlete? If not, why do you want to use roids? Just for the sake of being bigger and stronger or leaner? If that's the case, I would wait quite some time and weigh the risks, because if anything goes roid-related goes wrong with your body and health, then it's on you. And I say this because with a 135 bench you are likely very young (I might be wrong).
Your diet is fine, so long as you are not getting fat from it.
There is little advice to be offered if we don't see your whole program and how long you gave 5 x 5 or any other program a shot.
How old are you? Aside from your height, are you small, medium, or big framed? Actually, come to think of it, if you are very young, a 135 x 10 bench might give you a low 200's bench, which is not terrible for a very young guy your size (IF you are young, like high school age). Many here would disagree with me on this, but my standards are relative to what average guys can do, being an average myself. If we are to look at phenoms, then yes, most men are weak.