If you fall, just pick up and start again. Drop the self pity--the yeitzer hara wants us to have that self pity even more than he wants us to fall. It's the self pity that drags us down further and further.
Don't be so hard on yourself. It doesn't help things.
It sounds like you are STRUGGLING really hard. Trying to resist the urge to act out. Then, trying to convince yourself that you really don't want to do it. Either way, you're struggling. You're using up tons of energy, which is generally all negative energy.
Try, instead, to SURRENDER. First of all, instead of focusing on acting out or not acting out, on why you should or shouldn't, on what it will do to you (or for you), get your mind busy with something else. Get involved with life. And also start sharing with us about the rest of your life--how are things going with your family, with work, with learning, etc. What's going well, and what are you finding difficult, frustratring, or even unbearable. Don't just write about if you had an urge or not, if you fell or not.
Besides that, you're trying to do it on your own, basically. I have found that it doesn't work. Somehow, if I tell myself, "I'M NOT GOING TO ACT OUT; I'M GOING TO STOP MYSELF" it gets worse and worse and eventually I act out.
If, instead, I say, "G-d, I surrender my lust to you. Please save me from lust," (and sometimes I need to say it over and over again), but the result is that, in the end, the lust passes by. It disappears. It may come back eventually, but then it's a different wave of lust--it's not the same struggle schlepping on without stop for days or weeks on end.
--Elyah
