Oy, I wish Guard was here.... >
Anyway, your questions are good.. but there are good answers.
Basically, yes, of course, if we 'felt' in our bones that Hashem is watching us... we would not be nichshal. We would also be learning like crazy EVERY free second, we would eat just enough to keep us healthy, we would smile at everyone that passed by (men only, actually)... you get the idea.
So, to expect that you will conquer this one with Yiras shomayim alone, or, that you are expected at the tender age of 18 (just a guess
) to have this level of Yiras shomayim... sorry, it is not realistic.
Check the handbook where Guard quotes a Gemara where the Amora felt an urge to sin and quickly woke up the neighborhood so that he would not be alone... he did NOT medidate or even say krias shema etc....
When people here say it is a disease etc, that is refering to chronic abuse. At that stage, the person looses bechira pretty much, except to choose to avoid the nisayon altogether....
YOu likely are not up to that stage, but no matter... the tools that work for them will work for you...