Teens - Confessions

I was much more involved with masturbation and pornography months and months ago. In fact, it started when I was 11. The porn and the masturbation, though the porn was not prevalent until a few years later, because I was caught one time. After that, I have managed to never be caught. Earlier this summer I was at Challenge 2012, and for a while, I had myself off the porn for 2 or 3 weeks. Although the masturbation came back rather quickly. Embarrassingly enough, I slipped up with masturbating during Challenge. Yikes. Though I was really in tune with God, I even figured out my life path, Ministry. Unfortunately here I am, on the verge of a total relapse. My pastor knows full well of my problems, but now? I almost don't feel worthy enough to follow his footsteps into pastorship. It is killing me. I want to be God's servant, his voice, yet, I am struggling with lust and I can't seem to ignore it. I pray, I read my bible, I lead a bible study at school. At school I don't have issues with swearing or lustful thoughts, and then I get home and the thoughts are there. I just want people to know what I am struggling with, and asking for some heavy duty prayer. Actually last week I found out an old pastor of mine resigned because he had an affair. I don't want to be that guy. I can't be that guy. How do I fight it, if praying doesn't seem to be enough? Is there something in me, that is pulling harder than my desire to be Godly? What can I do? What can I let God do more?