If I can add - Fell Shmell is also a way of fighting the yetzer hora's true goal - which is getting you exactly where you are right now. Down, depressed, feeling like you can't get up, like you can't kiss a sefer torah without feeling ashamed. Low.
That's the yetzer hora talking to you - he won once, don't let him win again - feel good about your victories, and move forward to ward more victories. Feel proud of how much progress you've made, you're one in a million!
And remember - 90 days is a specific milestone, but even after that, there will still be temptations - sometimes strong ones. And even before 90, each day that you get further away from acting out, you get a little more clarity. You get a little healthier.
ONE DAY AT A TIME.
And one more point - after we fall, we realize that the yetzer hora was lying. It stinks. But it's possible to remember that beforehand, too. Check out this post of mine:
www.guardyoureyes.org/forum/index.php?topic=1315.msg43785;topicseen#msg43785