Sorry to hear you slipped hard. There's no doubt about it, though: PMO does bring immense pleasure. The problem is that the pleasure from PMO doesn't solve any problems and only makes them worse.
A little while ago, I was listening to something that said that our addictions are our brain's way of taking care of us when we feel we're in trouble. If we feel miserable and depressed, our brain knows that PMO will give us a shot of chemical to make us feel better. It works every time so our brain keeps pushing us back to it. But then we get stuck in addiction, and our lives get worse.
So it might be worth taking another step back. Instead of just focusing on quitting PMO, take some time to think about why you feel down in the dumps. Where is the despair coming from? And then, instead of escaping from your emotions through PMO, think about what you can actually do to address your pain. For me, relapses usually come because I feel sad about being single, because I get too stressed with school, or because I feel stuck or frustrated about something else. That realization has helped me to see that PMO is not just about PMO, but it's about solving more basic problems in my life and learning to deal with my emotions in healthier and more positive ways.
So definitely keep working on cutting PMO out of your life, but also make sure that you're also finding ways to take care of yourself and to find healthier ways of dealing with your sadness. That has made a huge difference for me, and I think it could help you too.