Well it's been quite a while. And I just want to confess that I have fallen again to pornography and I reread parts of your earlier note about repentance. I must say, it cheers me up nearly every time. Satan is still trying to condemn me and confuse my attitude toward my repentance and saying "You haven't truly repented! You don't want to go back! God can forgive you, but you're not doing it right!"
I'm pretty sure it's Satan and I do want to continue to resist. But, as with every fall, I do feel condemned, and I feel awful. I know I should get right back up, but it's always a "huge blast of energy toward God" and it wears out after a few days. I really want to continue after the few days as it keeps me away from sin. And especially with the stress I've been feeling with school.
You are correct that one of Satan's goals is to try to get people to give up. Guilt over sin has a purpose. It is there to remind us not to repeat a sin, but like other things, Satan can twist it to make people decide they can never be good and give up. The easiest sneak attack is to take something you have to do and either convince you that you have to do it sinfully or convince you that doing it is in itself a sin. Either way, every time you do it, you become further convinced that you can't be righteous.
As a male, you have to ejaculate; it is just how the body was designed. What you have to realize is that you don't have to do it with pornography. What I typically suggest is that you not to try giving up ejaculating because that is bound to fail. Worse, as semen builds up in your body, the body gets desperate for release and drives you to use the quickest known way to get an ejaculation out of you, which you've established as pornography through past habits. Instead, you allow yourself to masturbate, but only in the shower. One, you can't access pornography there; two, it is private; and three, clean up is easy.
The second half is dealing with lustful thoughts and that is done by teaching yourself self-control. Instead of masturbating simply for the pleasure of it, you pay attention to your body and your need to ejaculate. When you feel the need rise strongly, you take care of the need in the shower. But because you are waiting until the need is present, you don't have to dip into lustful thoughts to get your body aroused -- it is already aroused because of the need to ejaculate. It will be a struggle to maintain control of your thoughts, but it can be done.