I'm yet to know someone who quit porn on his first try. All of us here have relapsed a tone of times. As much as I hate to relapse, it is part of the process because relapses are an invitation to analyze my porn behavior. I think about what made me relapse and I take notes. It could help you writing here in your journal or writing in a private diary how you relapsed and keep track. You probably won't succeed until you learn your porn behavior: All the habits, routines, things you do that lead to relapse.
I'll try to give you some advice:
1) Accept that you have to suffer to quit porn. Porn is an addiction and as every addiction, withdrawal starts when you try to quit. Urges can be suffocating. They are suffering and suffering sucks. But it is inevitable. Nobody quits porn without the suffering of withdrawal. I used to rebel against this suffering. I said: "Fuck no! I don't want to suffer! I don't want urges! I didn't choose to be addicted to porn! I am a victim!" But no matter how much I screamed, the past couldn't be change and the fact still remained: I had to go through the suffering of withdrawal in order to quit this addiction. I had to accept that one day. When I started watching porn (and maybe yourself as well), there was no information about the harm effects of porn in my world. So of course I played the victim part and I didn't want to accept the suffering but life moves forward, not backwards. I can't go back in time and stop myself from becoming an addict, but I can move forward and quit porn.
2) Another withdrawal symptom is what I like to call "Porn in my head". All the flashbacks and images with porn scenes and pictures, probably porn induced fantasies, that come to your head whether you want it or not. You could be doing something, not thinking about porn at all and all of a sudden BAM! A porn flashback pops up in your mind. This is very annoying. Those flashbacks, images, fantasies create urges and craving and can push you to searching for porn if you engage with them. That's why you have to avoid them like the plague. Don't spend time watching that porn in your head, think about something else, look at something around you and concentrate on that object, think about how that object was made, what material is made of, if it's made of wood, think about trees, forest etc. I think you got the idea. Do something to distract yourself from giving attention to that porn stored in your brain. I've relapsed many times because I didn't listen to this. But now I have 2 weeks away from porn and I've been following this diligently.
3) Use your computer and cell phone only when you really need them. Don't spend time mindlessly surfing the Internet because sooner or later you will find something stimulating that will throw you off balance. When you need the computer, turn it on, do what you have to do, turn it off and walk away. Use your cellphone to call people, send messages and that's it. Use the Internet on your cell phone only when necessary. This is how you minimize the chance of encountering digital triggers. But there are other triggers as well. It could be girls on the street, advertisements around the city or feeling sad, disappointed, humiliated. Remember that porn doesn't heal anything. It doesn't make you get those girls from the streets, it doesn't get rid of the advertisements, it doesn't heal sadness, disappointment, humiliation etc. Porn doesn't help you in any way. Actually, porn is another problem, not a solution. Don't run home and PMO because of discomfort or triggers you encounter when you are out.
4) Find things to do during the day. Being bored has led me to relapse many times. It would be like: "Fuck, I have nothing to do I'm bored as fuck! Let me try to do something on my computer," and porn is one click away when you browse the Internet without a purpose.
5) Stay away from social media and I will repeat this: Stay away from social media! Quit Instagram, Facebook, Twitter everything because those places are full of triggers.
I don't know what else to say for now. Anyway, don't lose your motivation. A winner is a loser who just tried one more time. You don't have a chance to quit this addiction unless you keep trying.